Service

Caddy 1996 , Polo Classic 1996 ➤

Simosswainjection
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Service Department. Technical Information

 Service
List of Workshop Manual Repair GroupsList of Workshop Manual
Repair GroupsList of Workshop Manual Repair Groups
Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system

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01 - Self diagnosis ise nte
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24 - Mixture preparation, Injection ss c

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28 - Ignition system

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Technical information should always be available to the foremen and mechanics, because their careful
and constant adherence to the instructions is essential to ensure vehicle road-worthiness and safety. In
addition, the normal basic safety precautions for working on motor vehicles must, as a matter of course,
be observed.

All rights reserved.

No reproduction without prior agreement from publisher.

Copyright © 2011 Volkswagen AG, Wolfsburg 00056405320

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Contents

01 - Self diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1 Self diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.1 Self diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.2 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.3 Technical data of self diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.4 Connecting fault reader V.A.G 1551 and selecting engine electronics control unit . . . . . . . .2
1.5 Coding Simos control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
1.6 Interrogating and erasing fault memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.7 Fault table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
1.8 Final control diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
1.9 Read measured value block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
1.10 Display group overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

24 - Mixture preparation, Injection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

1 Simos injection and ignition system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
1.1 Simos injection and ignition system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
1.2 Fitting locations overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
1.3 Servicing injection part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
1.4 Dismantling and assembling intake manifold - upper part . . . . . . . . . . . . . . . . . . . . . . . . . .30
1.5 Dismantling and assembling intake manifold - lower part . . . . . . . . . . . . . . . . . . . . . . . . . .33
1.6 Dismantling and assembling air cleaner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
1.7 Safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
1.8 Rules for cleanliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
1.9 Technical data . . . . .a.ge. n. A.G. ..V.ol.ks. w. a.g.en. A. G
. .d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
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1.10 Idling check . . y.V.ol.ks. . . . . . . . . . . . . . . . . . . .s.no. t.g.u . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
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1.11 Performingrisbasic
ed setting . . . . . . . . . . . . . . . . . . . . r.an.te. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
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1.12 Checking au Lambda probe and Lambda control . . . . . . . .r a.c . . . . . . . . . . . . . . . . . . . . . . . . . . .38
th
s
1.13 Checking
s Lambda probe heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
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nl

1.14 Checking engine operating mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

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1.15 Checking intake manifold change-over valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

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1.16 Checking air mass meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46

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1.17 Checking throttle valve control part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48

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1.18 Checking coolant temperature sender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

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hole

1.19 Checking intake air temperature sender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57

spec
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1.20 Checking engine speed sender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

t to the co

1.21 Checking speed signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61

1.22 Checking control unit voltage supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
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1.23 Matching engine electronic control unit to electronic immobilizer . . . . . . . . . . . . . . . . . . . .65

1.24 Checking air conditioner and air conditioner compressor signals . . . . . . . . . . . . . . . . . . . .66
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1.25 Checking starter signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67

1.26 Checking injectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
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1.27 Checking fuel pressure regulator and holding pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . .70

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1.28 Checking intake air system for leaks (unmetered air) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
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28 - Ignition system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73

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1 Simos injection and ignition system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73

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1.1 Simos injection and ignition system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73

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1.2 Servicing ignition part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
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1.3 Safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
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1.4 Test data, spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
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1.5 Checking position of distributor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
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1.6 Removing and installing distributor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
1.7 Checking ignition timing control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
1.8 Checking Hall sender . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82

Contents i
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.9 Checking knock sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83

1.10 Checking ignition transformer and output stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85

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ii Contents
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

01 - Self diagnosis

1 - Self diagnosis
1.1 - Self diagnosis

Note:
The self-diagnosis monitors only a part of the injection and ignition system. For fault finding the binder "Fault
G. Volkswagen AG d
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1.2 - Function
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The Simos control unit (J361) for the fuel injection and ignition system is equipped with a fault memory.
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If faults occur in the sensors and components being monitored, they will be stored in the fault memory together

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The stored faults are output after initiating the fault display => Page 4 .

This fault memory must be erased once the faults have been eliminated => Page 4 . t to the co
rrectne

A fault relating to the function of the Lambda control system can only be interrogated after a test drive of at
least 10 minutes duration.
ss

Faults which can be attributed to a tempory open circuit in the wiring or a loose contact, will also be stored.
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These faults will be displayed as sporadic faults "SP" and are automatically cancelled if they are not repeated
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after 50 engine starts.

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1.3 - Technical data of self diagnosis

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1) Will be cancelled after 50th engine start if fault has not occurred again.

Control unit identification

=> Page 2 ; connecting fault reader V.A.G 1551 and selecting engine electronics control unit

Selectable functions

Function Ignition switched Engine idling

on
02 Interrogate fault - x
memory
03 Final control di‐ x -
agnosis
04 Introduction of x -
basic setting

1.1 - Self diagnosis 1

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

05 Erase fault mem‐ - x

ory
06 End output x x
07 Code control unit x -
08 Read measured x x
value block
10 Adaption x -

1.4 - Connecting fault reader V.A.G 1551 and selecting engine electronics control unit

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 with cable V.A.G 1551/3

Note: wage
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The vehicle system tester V.A.G 1552 rcanise be used instead of the fault reader V.A.G
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Test conditions

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• Fuse 21 OK.

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• Battery voltage at least 11 V

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• Earth connections on engine and gearbox OK.

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(Earth connection engine: =>Page 22 , Item 18 ).

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- -> Fold down left shelf.
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- Connect fault reader (or vehicle system tester) with cable V.A.G 1551/3. t. C rig
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Start engine => Page 1 , Table "Selectable functions".

Notes:
◆ If the display does not indicate as described in the work sequence:

=> Fault reader operating instructions

◆ If due to an input fault "Fault in the data transfer!" is displayed, pull wire off fault reader, reconnect and repeat
work step.

- Operate fault reader taking into account the information on the display:
- Press key 1 for "Rapid data transfer".

2 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Press keys 0 and 1 for address word "Engine electronics" and confirm entry with Q key.

-> The fault reader V.A.G 1551 display will show the control unit identification, e.g.:
6K0 906 025 SIMOS 4S2 3402
Coding 00000 WSC XXXXX

◆ 6K0 906 025 = Part No. of the control unit (for latest control unit version see parts catalogue)
◆ SIMOS 4S2 = System designation (4S) and
version (2) AG. Volkswagen AG d
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◆ 3402 = Programme level by
Vonumber
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◆ Coding 00000 = Coding
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◆ WSC = Workshoput code
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If the coding differs from the vehicle version, then:

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- Check control unit coding => Page 3 ,
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Coding Simos control unit

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- Press ⇒key.

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-> Indicated on display:

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Rapid data transfer HELP

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Select function XX

- Further measures see repair procedures.

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1.5 - Coding Simos control unit

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If the appropriate code for the vehicle is not displayed or if the control unit has been renewed, the control unit
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must be coded as follows.

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◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
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- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the ignition must be switched on.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 7 for the function "Code control unit" and confirm entry with Q key.

-> Indicated on display:

Code control unit Q
Input code number xxxxx (0-32000)

- Enter the appropriate code number for this vehicle and confirm with Q key.

Coding For vehicles with

00000 Manual gearbox

-> The fault reader V.A.G 1551 display will show the control unit identification, e.g.:
⇒
Coding 0000 WSC XXXXX

1.4 - Connecting fault reader V.A.G 1551 and selecting engine electronics control unit 3
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
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If an unauthorized code number is entered, the coding
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tomatically entered.

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- Press ⇒key.

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Rapid data transfer HELP

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Select function XX

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- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

Note:

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The code unit entered and shown on the display will not be used by the Simos control unit until the ignition has
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been switched off for at least 15 minutes.

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An incorrect coding leads to:

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◆ Engine running faults

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◆ Increased fuel consumption

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◆ Increased emissions
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◆ Faults stored in fault memory which are not actually present

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◆ Reduced gearbox life
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1.6 - Interrogating and erasing fault memory copy Vo
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Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 with cable V.A.G 1551/3

Note:

The vehicle system tester V.A.G 1552 can be used instead of the fault reader V.A.G 1551, however a print-out
is not possible.

Work sequence

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the engine must be running at idling speed.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

Only when engine does not start:

- Interrogate fault memory with ignition switched on.

- Switch on printer with the Print button

(Warning lamp in button lights up).

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Operate fault reader taking into account the information on the display:
- Press keys 0 and 2 for function "Interrogate fault memory" and confirm entry with Q key.

-> The number of faults stored or "No fault recognised!" will be shown on the display.
X Faults recognised!

4 01 - Self diagnosis
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Simos injection or and ignition system - Edition 11.1995
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If no fault is stored: ss

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- Press ⇒key.

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If one or more faults are stored:

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The faults stored will be displayed and printed out one after the other.

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Then the display will show:

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es, in part or in w

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- Locate and eliminate faults printed out as per fault table => Page 5 .
- Press keys 0 and 5 for the function "Erase fault memory" and confirm entry with Q key.

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-> Indicated on display:

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Rapid data transfer
Fault memory is erased!

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Note: mercia

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If the ignition is switched off between interrogating fault memory and erasing fault memory, the fault memory

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will not be erased.

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- Press ⇒key.
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-> Indicated on display:
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Rapid data transfer HELP gh ht
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- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

Note:
If a fault is present which is not recognised by the self diagnosis, carry out further fault finding using the fault
table in "Engine fault finding" binder.

1.7 - Fault table

Notes:
◆ The fault table is listed according to the 5 digit fault code on the left.
◆ Explanation of the fault types (e.g. "open circuit/short circuit to earth"):

=> Fault reader operating instructions

◆ Before renewing components indicated as being faulty, check the wiring and connectors to these compo‐
nents as well as the earth connections using current flow diagram. This is particularly relevant if faults are
output as "occurring sporadically" (SP).

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
00282
Throttle valve positioner -
V60-1)
Short circuit - Wiring open circuit or - Cold starting problems - Check V60 =>Page
short to earth/positive 48 , checking throttle
valve control part
- V60 defective/sticking - Cold idling problems
Open circuit - Wiring open circuit - Hard load change
- V60 defective/sticking - Mechanical emergency
running (J338) recog‐
nized

1.6 - Interrogating and erasing fault memory 5

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
Mechanical fault - V60 defective/sticking
Connectors - Cables interchanged

1) The throttle valve positioner V60 is a component of the throttle valve control part J338.

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
00513
Engine speed sender -G28
Signal outside tolerance - Gap speed sender/sender - Engine will not start - Check G28 for tight fit/metal
wheel too large particles
=> Page 28 , item 26
- Metal particles on G28 or - Check sender wheel for tight
retaining base loose fit:
- Sender wheel loose => Repair group 13; Disman‐
tling and assembling cylinder
n AG. Volkswagenblock, crankshaft and fly‐
es n wheel
AG do
lkswage
o ot g
yV
- Wiring open circuit or short db - Check G28=> ua Page 60
ran
ir se
circuit tho tee
or
u
- Loose contact ss
a ac

ce
e

- G28 defective - Replace G28

nl

pt
du

=> Page 28 , item 26

an
itte

y li
erm

ab
ility
V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
ot p

wit
, is n

00515

h re
hole

Hall sender -G40

spec
Signal outside tolerance - G40 defective - Governed speed approx. - Check G40
es, in part or in w

t to the co
5000 rpm => Page 82
- Wiring open circuit - Reduced performance
- Wire has short to positive - Poor starting

rrectness of i
- Wire has short to earth - High fuel consumption
l purpos

- Loose contact
- TDC marking not aligned - Check distributor setting

nf
ercia

at distributor => Page 77

orm
m

- Distributor loose / turned

atio
om

n in
or c

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
thi
te

sd
iva

00516
o
r
rp

cu
o

Idling switch -F601)

m
f

en
ng

t.
yi
implausible signal - F60 defective - Engine running problems - Check F60 =>Page 48 ,
Co
op py
when pulling away checking throttle valve control
t. C rig
gh ht
yri
part
p by
co Vo
by lksw
Open circuit - Wiring open circuit - Engine running problems cted agen
Prote AG.
during transfer from idling/
overrun to part load
Short to earth - Short to earth
- Short to positive

1) The idling switch F60 is a component of the throttle valve control part J338.

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
00518
Throttle valve potentiometer - - G69 defective
G691)

6 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
Short to earth - Wiring open circuit - Hard load change - Check G69 =>Page 48 ,
checking throttle valve con‐
trol part
- Wire has short to earth
Open circuit/short to posi‐ - Wiring open circuit in
tive earth wire
- Wire has short to positive
- G69 defective
implausible signal - Loose contact
- G69 defective

1) The throttle valve potentiometer G69 is a component of the throttle valve control part J338.

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
00520
Air mass/flow meter -G70/G19
Open circuit/short to positive - Wiring open circuit or short to pos‐ - Engine running problems - Check G70
itive =>Page 46
- G70 defective
Open circuit/short to earth - Wiring open circuit or short to
earth
- G70 defective

V.A.G 1551 print-out agen AG. Volkswagen Possible

AG do
es n
causes of fault Possible effects Fault remedy
lksw
00522 yV
o ot gu
db ara
rise
Coolant temperature sender -G62 nte
tho eo
Short
ss a to earth
u
- Wire has short to
ra
cearth - Poor cold starting - Check G62
=>Page 55
ce
e
nl

pt
du

- G62 defective - Poor hot starting

an
itte

y li

Open circuit/short to positive - Wiring open circuit

erm

ab
ility
ot p

- Wire has short to positive

wit
, is n

- G62 defective
h re
hole

implausible signal - G62 defective

spec
es, in part or in w

t to the co

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
00523
rrectness of i

Intake air temperature sender -

G42
l purpos

Short to earth - Wire has short to earth - Poor hot starting - Check G42=>Page 57
- G42 defective
nform
ercia

Open circuit/short to positive - Wiring open circuit or short

m

to positive
at
om

io

- G42 defective
n
c

in t
or

his
ate

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
do
priv

cum
or

00524
f

en
ng

t.
yi
Knock sensor 1 -G61
Co
Cop py
no signal - Wiring open circuit or short to - Reduced performance - Check G61
t. rig
gh ht
yri by
earth => Page 83
cop Vo
by lksw
cted
- No knock recognition from Si‐ - High fuel consumption
agen
Prote AG.
mos control unit (J361)
- G61 defective - Replace G61 => Page 74 ,
item 7

1.7 - Fault table 7

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
signal too large - No knock recognition from Si‐ - If necessary replace J361,
mos control unit (J361) => Page 25 , item 9
- G61 defective - Replace G61 => Page 74 ,
item 7

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
00525
AG. Volkswagen AG d
Lambda probe -G39 agen oes
olksw not
yV gu
no signal - Wiring open circuit or short ed - No Lambda control - Check Lambda
b ara probe
nte
and
is
to positive hor Lambda control eo
aut =>Page 38 ra
ss c
- G39 defective - Fuel smell

ce
le
un

pt
Open circuit/short to earth - Wiring open circuit or short

an
d
itte

y li
to earth
erm

ab
ility
- G39 defective
ot p

wit
is n

Short to positive - Wiring open circuit or short

h re
ole,

to positive

spec
urposes, in part or in wh

- G39 defective

t to the co
signal too small - Lambda probe heating de‐ - Check Lambda probe heat‐
fective ing=> Page 42
implausible signal - G39 defective

rrectne
V.A.G 1551 print-out Possible causes of Possible effects Fault remedy

ss
fault

o
cial p

f in
00530

form
mer

Throttle valve positioner/potenti‐

atio
m

ometer -G881)
o

n
c

i
Open circuit/short to - Wiring open circuit or - Cold starting problems - Check G88 =>Page
or

n thi
e

earth short to earth 48 , checking throttle

t

sd
va

valve control part

i

o
pr

cum
r
fo

- G88 defective - Cold idling problems

en
ng

t.
yi Co
Open circuit/short to - Wiring open circuit in - Hard load change Cop py
. rig
positive earth wire
ht ht
rig by
py
- Wire has short to pos‐ - mech. emergency run‐
co Vo
by lksw
cted agen
itive ning (J338) recognized Prote AG.

- G88 defective - Rough idling

implausible signal - Connector incorrectly
wired
Control difference - G88 defective
Control limit exceeded

1) The throttle valve positioner/potentiometer G88 is a component of the throttle valve control part J338.

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
00532
Supply voltage
Signal too large - Battery voltage - Engine running problems - Check alternator:
- exceeds 23.9 V => Current flow diagrams, Electri‐
cal fault finding and Fitting loca‐
tions binder

8 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
olkswagen AG
en AG. V
V.A.G 1551 print-out Possible causes ksw of fault Possible effects
ag does
not Fault remedy
y Vol gu
Signal too small - Battery ise
d b
voltage ara
nte - Check battery
- uless
thor
than 6.3 V eo Check earth connections
ss-a Poor earth connection ra
c => Current flow diagrams, Electri‐
cal fault finding and Fitting loca‐

ce
le
un

pt
tions binder

an
d
itte

y li
rm

ab
V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
pe

ility
ot

00533

wit
, is n

h re
Idling control
hole

spec
Lower limit value - Throttle valve positioner - Engine running problems - Check V60=>Page 72
es, in part or in w

(V60) sticking - High fuel consumption

t to the co
- Unmetered air to throttle - Fuel odours
valve

rrectness of i
- Injector defective - Check N30...N33
=> Page 67 , Checking injec‐
l purpos

tors
Upper limit value - Throttle valve positioner

nform
ercia

(V60) sticking
- Air filter blocked - Check air filter, renew if nec‐
m

a
com

t
essary

ion in
r
te o

thi
V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy

s
iva

do
r

00537
rp

cum
fo

en
g

Lambda control
n

t.
yi Co
op
upper limit value - Short to earth - No Lambda control
- Check Lambda probe and
C py
t. rig
Lambda control
gh ht
pyri by
=>Page 38
co Vo
by lksw
cted agen
- Injector defective (blocked) - Engine running problems - Check N30...N33
Prote AG.

=> Page 67 , Checking in‐

jectors
- Fuel pressure regulator de‐ - Check fuel pressure regula‐
fective tor => Page 70
- Fuel pump defective - Check fuel pump => Repair
group 20
- Fuel tank empty - Check fuel in fuel tank
lower limit value - see next page

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
00537
Lambda control continued
Lower limit value - Activated charcoal filter sol‐ - Check N80 => Page 12 , Final
enoid valve 1 (N80) leaking/ control diagnosis
sticking
- Injector defective (not clos‐ - Check N30...N33
ing completely) => Page 67 , Checking injectors
- Fuel pressure regulator de‐ - Check fuel pressure regulator =>
fective Page 70

V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
00546
Data wire defective
Short to positive - Short to positive - No effects - Check wire from control unit to diagnostic
connector according to current flow diagram:
=> Current flow diagrams, Electrical fault find‐
ing and Fitting locations binder

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
00624

1.7 - Fault table 9

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
Air conditioner compressor
cut-in
Short to positive - Wiring open circuit or - Hard load changes at - Check air conditioner re‐
short to positive small throttle valve angles lay:
- Rough idling Check wiring to air condi‐
-agIdling
en AG. speed
Volkswagdrops
en AG when tioner:
does
olks switching air conditioner not => Current flow diagrams,
w
yV gu
ised b on Electrical
ara
nte fault finding and
thor Fitting e locations
o binder
au ra
00625 ss c

ce
Speed signal le
un

pt
an
d

Signal outside tolerance - No signal from speed‐ - Speedometer not indi‐ - Check signal from G21/
itte

y li
erm

ometer (G21) or speed‐ cating correctly G22 =>Page 61 ,

ab
ility
ometer sender (G22) checking speed signal
ot p

wit
is n

- Increased idling speed

h re
ole,

- Engine running problems

spec
urposes, in part or in wh

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy

t to the co
00635
Lambda probe heating before

rrectne
Catalyst
Open circuit/short to - Wiring open circuit/ - Fuel smell - Check Lambda probe
positive short to positive heating =>Page 42

ss o
- G39 defective - Check wiring for short to
cial p

f in
positive/earth:

form
mer

=> Current flow diagrams,

atio
m

Electrical fault finding and

o

n
c

Fitting locations binder

i
or

n thi
e

Short to earth - Short to earth

t

sd
iva

o
r

- G39 defective
p

cum
r
fo

en
ng

t.
yi Co
Output on V.A.G 1551 printer Possible causes of fault Possible effects . Cop Fault remedy
py
rig
ht
01243 rig ht
py by
co Vo
Intake manifold change-over
by lksw
cted agen
valve -N156
Prote AG.

Open/short circuit to - Wire open/short circuit - Hard governor control - Check activation
earth to earth caused by switching in‐ => Page 12 , Final
jectors off at approx. control diagnosis
6500 rpm
- N156 defective - Acceleration problems
Short to positive - Short to positive
- N156 defective

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
01247
Activated charcoal filter sole‐
noid valve 1 -N80
Signal to positive - Wiring has short to - Rough idling - Check N80 => Page
positive 12 , final control diagno‐
sis
- N80 defective - Fuel smell
Open circuit/short to - Wiring open circuit/
positive short to positive
- N80 defective
V.A.G 1551 print-out Possible causes of fault Possible effects Fault remedy
01249
No.1 cyl. injector -N30

10 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
Open circuit/short to - Wiring open circuit or - Poor starting - Check N30...N33 => Page
positive short to positive 67 , checking injectors
- N30 defective - Poor performance
Short to earth - Short to earth - Engine will not start
- N30 defective
01250
No. 2 cyl. injector -N31
Open circuit/short to => No. 1 Cyl., fault code => No. 1 Cyl., fault code => No. 1 Cyl., fault code
positive 01249 01249 01249
Short to earth
Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
01251
AG. Volkswagen AG d
No. 3 cyl. injector -N32 agen oes
olksw not
yV gu
Openiscircuit/short
ed b to => No. 1 Cyl., fault code ara => No. 1 Cyl., fault code
nte => No. 1 Cyl., fault code
positive
hor 01249 01249
eo 01249
aut ra
Short
ss to earth c

ce
e

01252
nl

pt
du

an
itte

No. 4 cyl. injector -N33

y li
erm

ab
Open circuit/short to => No. 1 Cyl., fault code => No. 1 Cyl., fault code => No. 1 Cyl., fault code

ility
ot p

positive 01249 01249 01249

wit
, is n

h re
Short to earth
hole

spec
Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
es, in part or in w

01259 t to the co
Fuel pump relay -J17
Short to positive - Short to positive - Engine will not start - Check J17 => Page
rrectness of i

12 , final control diagno‐

sis
l purpos

Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
nform
ercia

17978
m

at

Engine control unit blocked - Attempted manipulation - Engine will not start - Match engine electronic
om

ion

control unit to the electron‐

c

in t
or

ic immobilizer => Page

his
ate

65
do
priv

cum

- Short in the communica‐ - Check electronic immo‐

for

en
g

tion wire bilizer:

n

t.
yi Co
op
=> Repair group 96; Serv‐
C py
t. rig
gh
icing electronic immobiliz‐
ht
yri by
er
op Vo
by c lksw
cted agen
- Incorrect coding Prote AG.

- Immobilizer control unit

defective/missing
Output on V.A.G 1551 printer Possible causes of fault Possible effects Fault remedy
65535
Control unit defective - Control unit internally - Engine running prob‐ - Renew J361 if necessa‐
defective lems ry,
=> Page 25 , item 9
defective - Engine will not start

1.7 - Fault table 11

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.8 - Final control diagnosis

The final control diagnosis activates the following components in the stated sequence:

1. Fuel pump relay (J17)

2. Activated charcoal filter solenoid valve 1 (N80)
3. Intake manifold change-over valve (N156), (two-
way valve)

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 with cable V.A.G 1551/3

◆ Test box V.A.G 1598/18
◆ Adapter set V.A.G 1594
◆ Diode test lamp V.A.G 1527
◆ Current flow diagram

Test conditions

• Fuse 15,18 and 21 OK.

Work sequence

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the ignition must be switched on.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP gen AG. Volkswagen AG d
a oes
Select function XX ksw not
y gu Vol
db ara
rise nte
- Operate fault reader
utho
taking into account the information on the e o display:
r
- a
Press keys 0ss and 3 for the function "Final control diagnosis". ac
ce
e
nl

pt
du

-> Indicated on display:

an
itte

y li
erm

ab

Rapid data transfer Q

ility

03 Final control diagnosis

ot p

wit
, is n

h re

Activating fuel pump relay (J17):

hole

spec
es, in part or in w

- Confirm input with Q key.

t to the co

-> Indicated on display:

rrectness of i

Final control diagnosis

Fuel pump relay J17
l purpos

The fuel pump relay (on the relay plate with fuse box, relay position 12) must click until switching to the next
final control by pressing the ⇒button.
nf
ercia

orm
m

Note:
atio
om

n in
or c

During the activation of the fuel pump relay the fuel pump must be heard to run at intervals.
thi
te

sd
iva

o
r
rp

cu

If the relay does not click:

o

m
f

en
ng

t.
yi Co
- Check fuel pump relay: Cop py
t. rig
gh ht
pyri by
=> Current flow diagrams, Electrical fault finding and Fitting locations, Fuel supply system.
co Vo
by lksw
cted agen
Prote AG.

12 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
Activating activated charcoal filter solenoid valve 1 (N80):
Test conditions
AG. Volkswagen AG d
• Fuse 15 OK. agen oes
olksw not
y V gu
d b ara
- Press ⇒key. rise nte
tho eo
au ra
s c
-> Indicated on display: s

ce
le
un

pt
Final control diagnosis

an
d
itte

Solenoid valve 1 for activated charcoal

y li
erm

ab
filter N80

ility
ot p

The activated charcoal filter solenoid valve 1 (under air cleaner housing) must click until the next final control

wit
is n

h re
element is selected by pressing the ⇒ button.
ole,

spec
urposes, in part or in wh

The valve clicks but a fault is still suspected (valve does not open or close):

t to the co
- Remove air filter.
- Pull hose off solenoid valve (from activated charcoal filter).

rrectne
- Connect auxiliary hose.
- During final control diagnosis blow into auxiliary hose (in direction of throttle housing).
Valve must open and close

ss o
cial p

f in
If the solenoid valve does not click:

form
mer

atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

- -> Pull 2 pin connector off valve and connect diode test lamp V.A.G 1527 with aux. cables from V.A.G 1594
to disconnected connector.
The LED must flash

LED flashes:
- Renew solenoid valve.

LED does not flash:

- Switch off ignition.

1.8 - Final control diagnosis 13

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- -> Connect test box V.A.G 1598/18 to control unit wiring loom -arrow-.
- Check wire between test box socket 33+2 pin connector contact 1 for open
swa
gen AGcircuit according
. Volkswagen AG
doesto current flow
diagram. y Volk not
gu
Wire resistance: Max. 1.5 ω edb ara
ris nt ee
tho or
au ac
If no fault in wire is detected: ss

ce
le
un

pt
- Check solenoid valve voltage supply according to current flow diagram, if necessary renew Simos control

an
d
itte

y li
unit (J361).

rm

ab
pe

ility
ot
Activate intake manifold change-over valve (N156):

wit
, is n

h re
hole
- Press ⇒key.

spec
es, in part or in w

t to the co
-> Indicated on display:
Final control diagnosis
Intake manifold change-over valve -N156

rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
iva

do
r
rp

cum
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
o
by c lksw
cted agen
- -> Pull 2 pin connector -1- off valve -2- and connect diode test lamp V.A.G 1527 with aux. cables from V.A.G
Prote AG.

1594 to disconnected connector.

The LED must flash

LED does not flash:

- Switch off ignition.

- -> Connect test box V.A.G 1598/18 to control unit wiring loom -arrow-.
- Check wire between test box socket 22 and 2 pin connector contact 2 for open circuit according to current
flow diagram.
Wire resistance: Max. 1.5 ω

If no fault in wire is detected:

- Check intake manifold change-over valve (N156) voltage supply according to current flow diagram. 2 pin
connector contact 1 and vehicle earth.
Specification: min. 11 V

14 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
If the voltage supply is OK and no fault is present in the wiring:
- Check intake manifold change-over valve => Page 45 .
- Press ⇒key.

Note:
n AG. Volkswagen AG do
wage e
After completion
y V of the final control diagnosist ginput
olks s no
u
06 for "End output" function and confirm with Q.
db ara
ise nte
- Switch
tho off ignition.
r e or
au ac
ss

ce
e
nl

pt
du

an
1.9 - Read measured value block
itte

y li
erm

ab
ility
ot p

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address

wit
, is n

word" 01. When doing this the engine must be running at idling speed.

h re
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)
hole

spec
es, in part or in w

-> Indicated on display:

t to the co
Rapid data transfer HELP
Select function XX

rrectness of i
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
l purpos

-> Indicated on display:

nform
ercia

Read measured value block HELP

Input display group number XX
m

at
om

ion

- Enter relevant display group number and confirm entry with Q key.
c

in t
or

his
ate

Note:
do
priv

cum
for

en
g

To change to another display group proceed as follows:

n

t.
yi Co
Cop py
t. rig
Display group V.A.G 1551 V.A.G 1552
gh ht
pyri by
Vo
o
by c
Higher Press key 3 Press ↑key
lksw
cted agen
Prote AG.
Lower Press key 1 Press ↓key
Skip Press key C Press key C

Test conditions
• Vehicle stationary, engine idling
• Engine oil temperature min. 80 °C
• Electrical consumers switched off (radiator fan must not run during the check)
• Air conditioner switched off

1.10 - Display group overview

Evaluation of display group 00 =>Page 17

Display group 00 (decimal displayed value)

▪ Engine running at idling speed
Display zones Specification Corresponds to
1 2 3 4 5 6 7 8 9 10 Engine speed 24...28 768...896 rpm
Injection period 2...4 2...4 ms
Throttle valve angle 6...11 2.5...4.7 <°
Operational condition No consequence ---

1.8 - Final control diagnosis 15

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Display group 00 (decimal displayed value)

Additive learnt value for Lambda probe 0...20 0...0.64 ms
Lambda probe voltage 10...50 0.2...1.0 V
Engine load signal 30...45 11.7...17.5 %
Coolant temperature 120...150 80...110 °C
Battery voltage 115...161 12...16.5 V
Intake air temperature 60...110 20...70 °C

1) Up-to-date specifications:

=> Exhaust emissions test binder

Display zones
1 2 3 4
Display group 01
Display xxxx rpm xxx °C x.xx V xxxxxxxx
Specification 780...880 rpm2) 80...110 °C 0.2...1.0 V 00000010
Indicated Engine speed Coolant temperature Lambda probe voltage Adjustment conditions1)

Display group 02
kswagen AG
n AG. Volxx.xx
Display xxxx rpm swage ms does xx.xx V xxx °C
olk not
Specification 780...880by V rpm2) 2...4 ms gu
ara 12...16.5 V 20...70 °C
ed nte
ris
Indicated thEngine speed
o Injection period Battery
e o voltage Intake air temperature
au ra
c
ss
ce
le

Display group 03
un

pt
an
d
itte

Display xxxx rpm xxx % xx.x <° xxx %

y li
erm

ab

Specification 780...880 rpm2) 12...17 % 3.0...4.5 <° 13...20 %

ility
ot p

wit

Indicated Engine speed Engine load signal Throttle valve angle Throttle valve positioner duty cy‐
is n

h re

cle
ole,

spec
urposes, in part or in wh

1) Relevance of numbers in 8 digit number block => Page 18 .

t to the co

2) Up-to-date specifications:
rrectne

=> Exhaust emissions test binder

ss

Display zones
o
cial p

f in

1 2 3 4
form
mer

Display group 04
atio
om

Display xxxx rpm xxx % xxx km/h xxxxxxxx

n
c

i
or

n thi

Specification 780...880 rpm3) 12...17 % 0 km/h 01000000

te

sd
iva

o
r

Indicated Engine speed Engine load signal Speed signal Engine operating condition1)
p

cum
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fo

en
ng

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op
Display group 05 C py
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Display xxxx rpm xxx % x.xx ms xxxxxxxx
pyri by
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Specification 780...880 rpm cted
7...9 % --- 00001010
agen
Prote AG.

16 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Display zones
Indicated Engine speed Duty cycle valve for activa‐ Consumption signal Operating condition Lambda
ted charcoal filter control2)

1) Relevance of numbers in 8 digit number block => Page 18 .

2) Relevance of figures in 8 digit number block => Page 18 .
3) Up-to-date specifications:
=> Exhaust emissions test binder

Display zones
1 2 3 4
Display group 06
Display x.xx ms x.xx x.xx x.xx
Specification 0.00...0.60 ms 0.90...1.10 0.90...1.10 0.90...1.10
Indicated Learned value for Learned value for Learned value for throt‐ Learned value for throt‐
Lambda control at Lambda control in part/ tle valve positioner du‐ tle valve positioner du‐
idling speed (additive) full load range (multipli‐ ty cycle ty cycle for automatic
cative) gearbox

Display group 07
Display xx xx x.xx xxxxxxxx
Specification 57...60 or 1 5...8 0.80...1.20 00000000
Indicated Coordination Hall Coordination Hall Altitude correction val‐ Operating condition
sender to engine sender to engine ue throttle valve control
speed sender speed sender part1)

1) Relevance of figures in 8 digit number block => Page 18 .

Evaluating display group 00

Display zone: 1 Possible fault cause Fault elimination

More than 110 Intake agen Aair
G . Vtemperature
olkswagen AG sender
does - Check intake air temperature sender => Page 57
lksw not
Less than b60 y Vo gu
ara
ed
Displaythozone:
ris 2 Possible fault cause nte
eo Fault elimination
u ra
Less
ss than 115 Alternator defective
a - Check
c control unit voltage supply => Page 63
Battery discharged/defective Check alternator
ce
le
un

pt

Check battery
an
d
itte

y li

More than 161 Voltage regulator defective - Check voltage regulator

erm

ab
ility

Display zone: 3 Possible fault cause Fault elimination

ot p

wit
is n

More than 150 Coolant temperature sender - Check coolant temperature sender => Page 55
h re
ole,

Less than 120 Coolant temperature sender - Check thermostat => Repair group 19
spec
urposes, in part or in wh

Thermostat defective (open)

t to the co

Display zone: 4 Possible fault cause Fault elimination

More than 45 Consumer switched on - Switch off consumer
rrectne

Less than 30 Unmetered air - Check intake air system for leaks => Page 72
s

Display zone: 5 Possible fault cause Fault elimination

s o
cial p

Constant 79 Lambda control blocked - Check Lambda probe and Lambda control => Page 38
inform

Shortage of fuel Check fuel in tank

mer

atio
m

Display zone: 6 Possible fault cause Fault elimination

o

n
c

i
or

n thi

Adaption figure Oil dilution - Change oil or carry out a fast drive on country
te

sd
a

more than 201) roads

iv

o
pr

cum
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Cop py
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pyri by
Vo
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17
by lksw
cted agen
Prote AG. 1.10 - Display group overview
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Unmetered air in air intake system or exhaust - Check intake air system for leaks (unmetered
manifold/front pipe air) => Page 72
Check exhaust system => Repair group 26
Fuel pressure too high - Check fuel pressure regulator
=> Page 70
Fuel pressure too low
Injector leaking - Check injectors => Page 67
Injector not opening or only opening partially
Lambda probe heating - Check Lambda probe heating
=> Page 42

1) It is not possible to establish from adaption value, whether the idling mixture is being adapted in rich or
lean direction. AG. Volkswagen AG d
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k ol n ot g
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Display zone: 8 Possible faultoriscause
e Fault elimination
tee
th o
Less than 6 Unmetered or exhaust - Check
air in air intake
s au system (unme‐ intake air systemr afor
c leaks
manifold/front pipe s
tered air) => Page 72

ce
le

Check exhaust system => Repair group 26

un

pt
an
d
itte

More than 11 Basic setting of throttle valve control part has - Perform basic setting => Page 48

y li
erm

ab
not been completed Adjust throttle cable => Repair group 20

ility
ot p

Throttle valve control part defective

wit
is n

Throttle cable adjustment

h re
ole,

Display zone: 9 Possible fault cause Fault elimination

spec
urposes, in part or in wh

More than 4 Consumer switched on - Switch off consumer

t to the co
Lambda control on limit Check Lambda probe and Lambda control =>
Page 38
Less than 2 Fuel pressure regulator defective/hose fallen - Check fuel pressure regulator => Page

rrectne
off 70
Display zone: 10 Possible fault cause Fault elimination

ss o
Less than 24 Throttle valve control part defective - Check throttle valve control part => Page
cial p

f in
48

form
mer

More than 28 Throttle valve control part defective - Check throttle valve control part => Page

atio
m

Unmetered air 72
o

n
c

i
or

n thi
te

Relevance of figures in 8 digit number block for adjustment conditions and operating condition.
sd
iva

o
pr

cum
r
fo

Significance when displayed digit = 1

en
ng

t.
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op
x x x x x x x x Adjustment conditions (display group 01) Engine operating condition (display group 04) C py
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1 Not relevant Overrun yri
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1 Signal from automatic gearbox Idling cted agen
Prote AG.
1 Air conditioner compressor switched on Part load
1 Idling switch open Full load
1 Fault in the Lambda control Not relevant
1 Throttle valve opened Not relevant
1 Engine running Not relevant
1 Coolant temperature below 80 °C Not relevant

Relevance of figures in 8 digit number block for Lambda control and throttle valve control part.

Relevance when displayed digit = 1

x x x x x x x x Lambda control operating condition Throttle valve control part operating condition (display
(display group 05) group 07)
1 Coding for Syncro Mechanical emergency running
1 Not relevant Not relevant
1 Not relevant Adaption necessary

18 01 - Self diagnosis
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Relevance when displayed digit = 1

1 Lambda control at limit Adaption necessary
1 Lambda control active Not relevant
1 Fault in fault memory Adaption terminated (battery voltage too low)
1 Lambda probe operationally ready Adaption terminated (time exceeded)
1 Rich mixture (0 = lean mixture) Idling switch open

- Additional measures see Repair procedures:

Notes:

◆ Press ⇒ button to end read measured value block.

◆ After terminating read measured value block input 06 for "End output" function and confirm with Q.

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ab
pe

ility
ot

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hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

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tion in
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pyri by
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cted agen
Prote AG.

1.10 - Display group overview 19

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

24 - Mixture preparation, Injection

1 - Simos injection and ignition system

1.1 - Simos injection and ignition system

AG. Volkswagen AG d
agen oes
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V gu
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du

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spec
es, in part or in w

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mercia

at
om

ion
c

in t
or

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ate

do
priv

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for

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Cop py
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Prote
1.2 - Fitting locations overview
AG.

1 Activated charcoal filter solenoid valve 1 (N80)

◆ Below air cleaner
◆ Activated charcoal filter system

=> Repair group 20; removing and installing parts of the fuel supply system; servicing activated charcoal filter
system removing and installing parts of the fuel supply system servicing activated charcoal filter system
2 4 pin connector
◆ For Lambda probe and Lambda probe heating

20 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

3 Injector (N30...N33)
4 Throttle valve control part (J338)
5 Intake manifold change-over valve (N156)
6 Ignition transformer (N152)
◆ With output stage (N157)
◆ => Page 74 , item 4

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ility
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hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

orm
m

atio
m

7 Speedometer sender (G22)

o

n in
or c

8 Simos injection and ignition system control unit (J361)

thi
te

sd
iva

9 Coolant temperature sender (G62)

o
r
rp

cu

◆ Black, with temperature gauge sender (G2)

o

m
f

en
ng

t.
yi
10 Central connector
Co
Cop py
11 3 pin connector
t. rig
gh ht
pyri by
◆ For knock sensor
co Vo
by lksw
cted
◆ Blue
agen
Prote AG.

12 3 pin connector
◆ For engine speed sender
◆ Black
13 Engine speed sender (G28)
14 Distributor with Hall sender (G40)

1.2 - Fitting locations overview 21

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
◆ => Page 76 , item 15

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
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nl

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du

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es, in part or in w

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rrectness of i
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nf
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n in

15 Intake air temperature sender (G42)

or c

thi
e

16 Intake manifold change-over vacuum unit

t

sd
iva

o
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rp

cu

17 Knock sensor 1 (G61)

o

m
f

en
ng

◆ => Page 74 , item 7

t.
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op
18 Earth connection
C py
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by
19 Fuel pressure regulator copy Vo
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20 Air mass meter (G70) Prote AG.

21 Activated charcoal filter

◆ Below air cleaner
◆ Activated charcoal filter system

=> Repair group 20; removing and installing parts of the fuel supply system; servicing activated charcoal filter
system removing and installing parts of the fuel supply system servicing activated charcoal filter system

22 24 - Mixture preparation, Injection

 AG. Volkswagen AG d
agen oes
olksw not
V gu
d by Caddy 1996 a, raPolo Classic 1996 ➤
ise nte
r
ut
ho Simos injection and ignition systeme o-r Edition 11.1995
a ac
ss
1.3 - Servicing injection part

ce
le
un

pt
an
d
itte

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pe
Servicing ignition part

ility
ot

wit
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h re
=> Repair group 28
hole

spec
es, in part or in w
Notes:

t to the co
◆ Fuel hoses in engine compartment must only be secured with spring type clips. The use of clamp or screw
type clips is not permissible.

rrectness of i
◆ The control unit for the fuel injection and ignition system is equipped with a fault memory. Before carrying
out repairs, adjustment work and fault finding the fault memory must be interrogated and the vacuum con‐
l purpos

nections checked (outside air).

◆ Components marked with * are checked via the self diagnosis.

nform
ercia

=> Page 4 , interrogating fault memory

◆ Components marked with ** are checked via the final control control diagnosis => Page 12 .
m

a
◆ For trouble-free operation of the electrical components, a voltage of at least 11.5 V is necessary.
com

tion in
◆ Do not use sealants containing silicone. Particles of silicone drawn into the engine, will not be burnt in the
r
te o

engine and damage the Lambda probe.

thi
s
iva

do
r
rp

c
◆ If the engine starts, runs for a short period and then stops, after fault finding, repairs or component tests,

um
fo

en
g

then the fault may lie with the immobilizer which is blocking the engine control unit. The fault memory must
n

t.
yi Co
be interrogated and if necessary the control unit matched => Page 65 . Cop py
t. rig
◆ During some checks it can happen that the control unit will recognise and store a fault. Therefore after
yri
gh by
ht
completing all checks and repairs the fault memory must be interrogated and if necessary erased.
op Vo
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=> Page 4 , interrogating fault memory cted agen
Prote AG.

Safety precautions =>Page 35

Rules for cleanliness => Page 35

Technical data => Page 36

Checking engine operation => Page 44

1.3 - Servicing injection part 23

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c

ce
e
nl

pt
du

an
itte

y li
erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

at
om

ion
c

in t
or

his
ate

do
priv

cum
for

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

1 Air cleaner
◆ Dismantling and assembling => Page 34
2 Connector
◆ 3 pin
◆ For air mass meter (G70)
3 To crankcase
4 To cylinder head cover
5 Intake hose
6 Connector
◆ 8 pin
◆ For throttle valve control part (J338)
7 Intake manifold
◆ Dismantling and assembling upper part => Page 30
◆ Dismantling and assembling lower part => Page 33
8 Connector
◆ Only disconnect or connect with ignition switched off
◆ Unlatch to disconnect

24 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
e d
is nte
9 Simos control
hor unit (J361)* eo
ut ra
◆ Location:
ss a in plenum chamber, left c
◆ For injection system, throttle valve control part, Lambda regulation, knock control, activated charcoal
ce
e
nl

pt

filter solenoid valve 1, speed governing via injectors or fuel pump relay, ignition and self diagnosis
du

an
itte

◆ Voltage supply via voltage supply relay (J363) and terminal 15

y li
erm

ab

◆ Checking voltage supply => Page 63

ility
ot p

◆ Checking signal from starter

wit
, is n

=> Page 67
h re

If the control unit is replaced then the following work must be carried out:
hole

spec

◆ Check control unit coding => Page 3 , Coding Simos control unit
es, in part or in w

◆ Perform basic setting => Page 37

t to the co

◆ Match control unit to electronic immobilizer => Page 65

rrectness of i
l purpos

nform
mercia

at
om

ion
c

in t
or

his
ate

do
priv

cum
for

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo

25
by lksw
cted agen
Prote 1.3 - Servicing injection part
AG.
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
y V gu
d b ara
rise nte
tho eo
au ra
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nl

pt
du

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ab
ility
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hole

spec
es, in part or in w

t to the co
10 10 Nm
11 Securing plate
◆ For Simos control unit (J361) rrectness of i

12 20 Nm
l purpos

13 Support
◆ Between intake manifold and cylinder head cover
nform
ercia

14 Connector
◆ 2 pin
m

at
om

◆ For intake manifold change-over valve (N156)

on
c

in t
r

15 To brake servo
o

his
ate

16 20 Nm
do
priv

cum

17 Connector
for

en
ng

◆ 2 pin
t.
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op
◆ For intake air temperature sender (G42)
C py
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18 Seal p by
co Vo
by lksw
◆ Renew cted agen
Prote AG.

26 24 - Mixture preparation, Injection

 AG. Volkswagen AG d
agen
not Caddy 1996 , Polo Classic 1996 ➤
oes
olksw
yV gu
ed b Simos injection andara ignition system -
nte
Edition 11.1995
ris
ho eo
aut ra
ss c

ce
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un

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d
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pe

ility
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es, in part or in w

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rrectness of i
l purpos

nform
mercia

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com

tion in
r
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Cop py
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rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

19 Connector
◆ 2 pin
◆ For injector
20 25 Nm
21 Retaining clip
◆ Check seated securely
22 O ring
◆ Renew if damaged
23 Coolant temperature sender (G62)*
◆ Black, with temperature gauge sender (G2)
◆ For Simos control unit
◆ Checking => Page 55
◆ If necessary before removing, release pressure from cooling system
24 Connector
◆ 4 pin
◆ Wiring chamber 1 and wiring chamber 3 for G62
25 Intake rail - lower part

1.3 - Servicing injection part 27

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
y V gu
d b ara
rise nte
tho eo
au ra
ss c

ce
e
nl

pt
du

an
itte

y li
erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

at
om

ion
c

in t
or

his
ate

do
priv

cum
for

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

26 Engine speed sender (G28)*

◆ Checking => Page 60
27 10 Nm
28 Spacer ring
29 O ring
◆ Renew if damaged
30 3 pin connector
◆ For engine speed sender
◆ Black

28 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
V gu
d by ara
ise nte
or eo
h
aut ra
ss c

ce
e
nl

pt
du

an
itte

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erm

ab
ility
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wit
, is n

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hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

at
31 Lambda probe (G39)*, 50 Nm
om

ion
c

◆ Fitting location: front pipe

in t
or

◆ Grease only the threads with "G5"; "G5" must not get into the slots on the probe body
his
ate

◆ Checking Lambda probe and Lambda control

do
priv

=> Page 38
um
for

en
g

◆ Probe heating voltage supply via fuel pump relay (J17)

n

t.
yi Co
◆ Checking Lambda probe heating => Page 42 Cop py
t. rig
gh
32 4 pin connector
ht
pyri by
Vo
o
by c
◆ For Lambda probe and Lambda probe heating
lksw
cted agen
Prote
◆ Secured to rear engine mounting on right, in direction of travel
AG.

33 M6 = 10 Nm
M8 = 20 Nm
34 Deflector

1.3 - Servicing injection part 29

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.4 - Dismantling and assembling intake manifold - upper part

AG. Volkswagen AG d
agen oes
olksw not
V gu
d by ara
ise nte
or eo
h
aut ra
ss c

ce
le
un

pt
an
d
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pe

ility
ot

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hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

1 M6 = 10 Nm
M8 = 20 Nm
2 Throttle valve control part (J338)*
nform
ercia

◆ Checking => Page 48

m

◆ Components of the throttle valve control part (J338):

com

tion in

Throttle valve positioner (V60), throttle valve potentiometer (G88), throttle valve potentiometer (G69) and
r
te o

idling switch (F60)

thi
s
iva

◆ If replaced carry out basic setting => Page 37

do
r
rp

cum

3 To connection
fo

en
ng

t.
◆ On cylinder head
yi Co
op py
4 To expansion tank
t. C rig
gh ht
pyri by
5 Cover
o Vo
by c lksw
cted agen
Prote AG.

30 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c

ce
le
un

pt
an
d
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y li
rm

ab
pe

ility
ot

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
iva

do
r
rp

cum
fo

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

6 Support bracket
◆ For accelerator cable
◆ Adjusting accelerator cable

=> Repair group 20, removing and installing parts of the fuel supply system, adjusting accelerator cable

7 Retaining clip
◆ For coolant hose
8 Intake manifold - upper part
9 To brake servo
10 Retaining clip
◆ For accelerator cable
11 Retaining clip
◆ For coolant hose
12 Angled piece
13 Intake manifold change-over valve (N156)*/**
◆ Checking => Page 45
14 Vacuum hose/pipe

1.4 - Dismantling and assembling intake manifold - upper part 31

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
ed
ris nte
ho eo
aut ra
ss c

ce
e
nl

pt
du

an
itte

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erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

orm
m

atio
om

n in
or c

thi
te

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iva

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cu
o

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f

en
ng

t.
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Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

15 Vacuum reservoir
◆ For intake manifold change-over at full load
16 Vacuum unit
◆ For intake manifold change-over
17 Intake air temperature sender (G42)*
◆ Checking => Page 57
18 O ring
◆ Renew if damaged
19 Vacuum connection
◆ For fuel pressure regulator
20 To intake hose
21 Seal
◆ Renew

32 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.5 - Dismantling and assembling intake manifold - lower part

AG. Volkswagen AG d
agen oes
olksw not
V gu
d by ara
ise nte
or eo
h
aut ra
ss c

ce
le
un

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an
d
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ot

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es, in part or in w

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l purpos

nform
mercia

a
com

tion in
r
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thi
s
iva

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cum
fo

en
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Cop py
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Vo
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by c lksw
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Prote AG.

1 Retaining clip
◆ Check securely seated
2 Strainer
3 Fuel pressure regulator
◆ Checking => Page 70
4 O ring
◆ Renew if damaged
5 Injectors (N30...N33)*
◆ Checking => Page 67
6 Intake rail - lower part
7 10 Nm
8 Fuel rail

1.5 - Dismantling and assembling intake manifold - lower part 33

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.6 - Dismantling and assembling air cleaner

AG. Volkswagen AG d
agen oes
olksw not
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aut ra
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ce
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un

pt
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d
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rm

ab
pe

ility
ot

wit
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hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
iva

do
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fo

en
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t.
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Cop py
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Prote AG.

1 Filter element
2 Air cleaner upper part
3 Air duct
4 Seal
◆ Renew if damaged
5 Air mass meter (G70)*
◆ Checking => Page 46
6 10 Nm
7 Air cleaner lower part
8 Packing
9 Retaining ring
10 Foam seal

34 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

-> Fig. 1 Resistance graph

The diagram is valid for coolant temperature sender (G62) and intake air sender (G42).

Scale A shows resistance values for temperature range 0...50 °C and scale B the values for temperature range
50...100 °C. swa
gen AG
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does
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Examples: ris
ed
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a
◆ 30 °C corresponds to a ω resistance
ss from 1500...2000 c

ce
◆ 80 °C corresponds to a resistance from 275...375 ω
e
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ab
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1.7 - Safety precautions

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spec
es, in part or in w

Warning!

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The fuel system is pressurized! Before loosening hose connections or opening the test connection, place a
cloth around the connection. Then carefully pull hose off or remove the plug.

rrectness of i
To prevent injuries to persons and/or damage to the fuel injection and ignition system, the following must be
l purpos

noted:
nform
ercia

◆ Do not touch or disconnect ignition wiring when the engine is running or being turned at starter speed.
◆ The ignition must be switched off before connecting or disconnecting injection or ignition system wiring or
m

at
om

tester cables.
ion
c

◆ If the engine is to be turned at starter speed, without starting, e.g. when checking compressions, pull 3 pin
in t
or

connector off ignition transformer.

his
ate

do
priv

cum
for

en
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t.
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1.8 - Rules for cleanliness
Co
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When working on the fuel supply/injection system, pay careful attention to the following "5 rules": Prote AG.

◆ Thoroughly clean all unions and the adjacent areas before disconnecting.
◆ Place parts that have been removed on a clean surface and cover. Do not use fluffy cloths!
◆ Carefully cover opened components or seal, if the repair cannot be carried out immediately.
◆ Only install clean components:
Only unpack replacement parts immediately prior to installation.
Do not use parts that have been stored loose (e.g. in tool boxes etc.).
◆ When the system is open:
Do not work with compressed air if this can be avoided.
Do not move vehicle unless absolutely necessary.

1.6 - Dismantling and assembling air cleaner 35

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.9 - Technical data

Engine code AFT

Idling check2)
Idling speed2) 790...8901)
Simos control unit3)
Part number => Parts catalogue
Max. engine speed rpm 6300...6500

1) Up-to-date specifications:

=> Exhaust emissions test binder

2) Not adjustable

3) If replaced carry out basic setting => Page 37

1.10 - Idling check

Notes:

◆ Idling speed, ignition timing and CO content not adjustable.

◆ The idling speed is regulated to specification by the throttle valve positioner in conjunction with the DIS
function.
◆ The position of the distributor has no influence on ignition timing.

◆ CO content regulated by Lambda regulation. Faults in Lambda control are detected in self-diagnosis and
stored in fault memory.

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 withAcable V.A.G 1551/3
G. Volkswagen
agen AG do
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Check conditions y Vol ot g
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ed ran
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• Engine oil temperature at least 80 °C sa
ut or
ac
• Electrical consumers switched off (radiator fans must not run during the check)
ce
e

• Air conditioner switched off

nl

pt
du

an

• Accelerator cable adjustment OK

itte

y li
erm

ab
ility

=> Repair group 20, removing and installing parts of the fuel supply system, adjusting accelerator cable
ot p

wit
, is n

h re

Test sequence
hole

spec
es, in part or in w

- Start engine and run at idling speed.

t to the co

- Interrogate fault memory, if necessary, repair fault and erase fault memory.
=> Page 4 , interrogating and erasing fault memory
- Then:
rrectness of i

- Leave fault reader V.A.G 1551 connected.

- Continue running engine at idling speed.
l purpos

-> Indicated on display:

nf
ercia

Rapid data transfer HELP

rm
m

Select function XX
atio
om

n in
or c

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
thi
te

sd
iva

o
r

-> Indicated on display:

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cu
o

m
f

en
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t.
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Cop py
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pyri by
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by
cted
36 24 - Mixture preparation, Injection
agen
Prote AG.
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Read measured value block HELP

Input display group number XX

- Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.

-> Indicated on display:

(1...4 = Display zones)
Read measured value block 1
1 2 3 4

olkswagen AG
en AG. V
Do not continue with check until a 1 appears
olks
wag in display zone 4 -d8
oedigit
s no number block - 00000010.
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ise
Note: r nte
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au ra
c
ss
If at one or more positions a 1 is displayed in display zone 4, the test conditions have not been fulfilled:

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le
un

pt
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d
itte

=>Page 18 ; Relevance of figures in 8 digit number block

y li
rm

ab
pe

ility
- Allow engine to idle for at least 1 minute.
ot

wit
, is n

- Check idling speed in display zone 1.

h re
Specification: 790...890 rpm1)
hole

spec
es, in part or in w

1) Up-to-date specifications:

t to the co
=> Exhaust emissions test binder

rrectness of i
- Press ⇒key.
l purpos

- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

If the specification is not obtained:

nform
mercia

a
- Perform basic setting => Page 37
com

tion in
- Carry out road test, interrogate fault memory again and repeat idling check.
r
te o

thi
s
iva

If the specifications are again not attained:

do
r
rp

cum
fo

en
g

- Check throttle valve control part

n

t.
yi Co
=> Page 48 . Cop py
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pyri by
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Prote AG.
1.11 - Performing basic setting

Note:

The basic setting matches the Simos control unit to the throttle valve control part with the ignition switched on.

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

Test conditions

• No faults stored in fault memory

=> Page 4 , interrogating fault memory

Test sequence

- Switch ignition on.

- Interrogate fault memory, if necessary, repair fault and erase fault memory.
=> Page 4 , interrogating and erasing fault memory

1.10 - Idling check 37

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Then:

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 4 for the function "Introduction of basic setting" and confirm entry with Q key.

-> Indicated on display:

Basic setting HELP
Input display group number XX

- Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.

-> Indicated on display:

(1...4 = Display zones)
System in basic setting 1
1 2 3 4

Note:

After confirming the display group number 01 the throttle valve positioner will be moved to the min., max. and
three intermediate positions and the control unit will store each individual throttle valve angle in the permanent
memory. The throttle valve will then remain in the start position.

- Terminate engine basic setting by pressing the⇒ button.

- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
- Switch off ignition.

Note:

The ignition must remain switched offsfor

wageat least 15 seconds
n AG. Volkswagen AG do so as to store the basic setting.
es
olk not
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- Check the operating mode ris of the throttle
e valve control part => Page nte49
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aut ra
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nl

pt

1.12 - Checking Lambda probe and Lambda control

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Special tools, testers and auxiliary items

wit
, is n

h re
hole

spec

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
es, in part or in w

◆ Test box V.A.G 1598/18

t to the co

◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715

◆ Adapter set V.A.G 1594
◆ Current flow diagram
rrectness of i

Check conditions
l purpos

• Coolant temperature at least 80 °C

nf
ercia

• Exhaust system between catalyst and cylinder head free of leaks

orm
m

atio
m

Functional check
o

n in
or c

thi
e

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
t

sd
iva

word" 01. When doing this the engine must be running at idling speed.
o
r
rp

cu

(Connecting fault reader and selecting engine electronics control unit => Page 2 .)
o

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op
-> Indicated on display:
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Rapid data transfer HELP co Vo
lksw
Select function XX by
cted agen
Prote AG.

38 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

-> Indicated on display:

Read measured value block HELP
Input display group number XX

- Press keys 0 and 5 for "Display group number 05" and confirm entry with Q key.

-> Indicated on display:

(1...4 = Display zones)
Read measured value block 5
1 2 3 4

- Checking Lambda control operating condition in display zone 4:

Lambda control operating condition display:

◆ Lambda control on stop:

5th position from right must display 0

Display:: 00000000
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◆ Lambda control active:lkswagen oes
not
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ed
4th position from
ho
r right must
is display 1 nte
eo
Display:s a00001000
ut ra
c
s ce
le

◆ Fault in fault memory:

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pt
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d
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3rd position from right must display 0

ab
pe

ility

Display:: 00000000
ot

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◆ Lambda probe operationally ready:

hole

spec
es, in part or in w

2nd position from right must display 1

t to the co

Display: 00000010

◆ Mixture:
rrectness of i
l purpos

1st position from right must display 0 and 1 alternately

Display: 00000001 (1 = rich mixture)
Display: 00000000 (0 = lean mixture)
nform
mercia

- Press C key.
a
com

tio

- Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.
n in
r
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thi

-> Indicated on display:

s
iva

do
r

(1...4 = Display zones)

rp

cum
fo

en
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Read measured value block 1

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1 2 3 4 Cop py
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- Observe Lambda probe voltage in display zone 3. The voltage must fluctuate
p by
co Vo
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at least 30 time per minute Prote
cted AG.
agen
in the range
0.2...1.0 V.

Display Cause Continuation of

check
approx. 2.51 V Short to positive => Page 40
Checking basic
voltage
approx. 1.52 V Open circuit => Page 41 ,
Checking wiring

1.12 - Checking Lambda probe and Lambda control 39

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Display Cause Continuation of

check
approx. 0.50 V Short to wire 2
approx. 0.15 V Short to earth
fluctuates be‐ Control OK. ---
tween 0...1.1 V

- Press ⇒key.
- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

If the specifications for Lambda control operating conditions are not attained or the probe voltage does not
fluctuate as stated:

- Check Lambda probe heating => Page 42 .

- Check Lambda probe for soot. Renew if necessary.
AG. Volkswagen AG d
Checking basic voltage lksw
agen oes
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ris nte
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d
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y li
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ab
pe

ility
ot

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hole

spec
es, in part or in w

t to the co
rrectness of i

- -> Separate 4 pin connector (black) to Lambda probe before catalyst (G39) -1-.
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
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do
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cum
fo

en
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t.
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Cop py
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rig ht
py by
co Vo
by lksw
cted agen
Prote AG.
- -> Connect multimeter with aux. cables from V.A.G 1594 to measure voltage at contacts 3+4 (connector to
engine control unit).
- Switch on ignition and measure basic voltage.
Specification: 1.30...1.40 V
- Switch off ignition.

If the specification is not obtained:

- Check Lambda probe wiring

=> Page 41

If the specification is attained:

- Replace Lambda probe (G39).

40 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
Checking Lambda probe wiring

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.

n AG. Volkswagen AG do
lkswage es n
o ot g
byV ua
d ran
ir se tee
tho
u or
a ac
ss

ce
le
un

pt
an
d
itte

y li
rm

ab
pe

ility
ot

wit
, is n

h re
- -> Separate 4 pin connector (black) to Lambda probe before catalyst (G39) -1-.
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
iva

do
r
rp

cum
fo

- -> Check wiring between test box and 4 pin connector for open circuit according to current flow diagram.
en
ng

t.
yi
Contact 3+socket 42
Co
op py
Contact 4+socket 17 t. C rig
gh ht
Wire resistance: Max. 1.5 ω yri
p by
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- Check wiring at 4 pin connector for short to one another.
by lksw
cted agen
Contact 1+socket 20
Prote AG.

Contact 1+socket 42
Contact 1+socket 17
Contact 2+socket 17
Contact 2+socket 42
Contact 3+socket 17
Specification: ∞ω
- Check screening wire -test box socket 21- for short to the probe wiring according to current flow diagram.
Contact 1+socket 21
Contact 2+socket 21
Contact 3+socket 21
Contact 4+socket 21
Specification: ∞ω

1.12 - Checking Lambda probe and Lambda control 41

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Additionally check all wiring for short to battery positive and to vehicle earth.

If a fault in wire is detected:

- Check wiring according to current flow diagram.

If no wiring fault is detected:

- Replace Lambda probe (G39).

1.13 - Checking Lambda probe heating

Special tools, testers and auxiliary items agen

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oes
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y V gu
b
◆ Test box V.A.G 1598/18 rise
d ara
nte
◆ Hand multimeter V.A.G 1526 or multimeter
utho V.A.G 1715 eo
ra
◆ Adapter set V.A.G 1594 ss a c
◆ Current flow diagram

ce
e
nl

pt
du

an
itte

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Test conditions
erm

ab
ility
ot p

• Fuel pump relay OK

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, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

orm
m

atio
om

n in
or c

thi
te

sd
a

• Fuse 18 OK
iv

o
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rp

cu
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m
f

en

Test sequence
ng

t.
yi Co
Cop py
t. rig
- -> Separate 4 pin connector (black) to Lambda probe before catalyst (G39) -1-. opyri
gh by
Vo
ht
c by lksw
cted agen
Prote AG.

- -> Check probe heating at connector contacts 1+2 for continuity

Specification: max. 200 ω

42 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
If the specification is not attained:

- Replace Lambda probe (G39).

If the specification is attained:

AG. Volkswagen AG d
agen oes
olksw not
- -> Connect multimeter d by V
to measure voltage at contacts gu1+2 of connector.
ara
- Switch on ignition.rise nte
ho eo
Specification:
s aut
approx. 4.5 V ra
c
- Start engine
s and run at idling speed.

ce
le

- -> Connect multimeter to measure voltage at contacts 1+2 of connector.

un

pt
an
d

- Switch off ignition.

itte

y li
rm

ab
pe

ility
If no voltage is present:
ot

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
s
iva

do
r
rp

cum
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

- -> Check wiring between test box and 4 pin connector for open circuit according to current flow diagram.
Contact 2+socket 20
Wire resistance: Max. 1.5 ω

If the specification is attained:

1.13 - Checking Lambda probe heating 43

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Check wiring from contact 1 to fuel pump relay (J17) according to current flow diagram.

1.14 - Checking engine operating mode

Note:

Check establishes whether Simos control unit (J361) recognises the engine operating modes.

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

Test conditions

• Coolant temperature at least 80 °C

Test sequence AG. Volkswagen AG d

agen oes
olksw not
yV gu
- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engineised b electronics control unit with the "Address
ara
nte
word" 01. When doing this the engine must be running at thidling
or speed. eo
(Connecting fault reader and selecting engine electronics
ss au
control unit => Page 2 .) ra
c

ce
le
un

pt
-> Indicated on display:

an
d
itte

y li
Rapid data transfer HELP
rm

ab
Select function XX
pe

ility
ot

wit
, is n

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

h re
hole

spec
-> Indicated on display:
es, in part or in w

t to the co
Read measured value block HELP
Input display group number XX

rrectness of i
- Press keys 0 and 4 for "Display group number 04" and confirm entry with Q key.
l purpos

-> Indicated on display:

(1...4 = Display zones)

nform
ercia

Read measured value block 4

m

a
1 2 3 4
com

tion in
r
te o

Display for operating modes:

thi
s
iva

do
r
rp

◆ Overrun mode:
um
fo

en
ng

t.
yi Co
- Increase engine speed to above 3000 rpm. t. Cop py
- Close throttle abruptly.
rig
gh ht
pyri by
Vo
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by c lksw
1st position from left must display 1 as long as the engine speed is above 1500 rpm
cted agen
Prote AG.
Display: 10000000

◆ Idling:

2nd position from left must display 1

Display: 01000000

◆ Part throttle:

- Rev up evenly.

3rd position from left must display 1

44 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
Display:: 00100000

◆ Full throttle:

- Floor accelerator pedal and release.

4th position from left must briefly display 1

Display: 00010000

Note:
Below 1500 rpm idling speed is again recognised.
- Press ⇒key.
- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

If the specifications are not attained:

- Interrogate and erase fault memory, eliminate faults if necessary => Page 4 .
- Check accelerator mechanism for ease of operation.
- Check throttle valve potentiometer
=> Page 48 , checking throttle valve control part.

1.15 - Checking intake manifold change-over valve

Test conditions

AG. Volkswagen AG d
agen oes
olksw not
V gu
d by ara
ise nte
or eo
h
aut ra
ss c
ce
le

• Activation OK. =>Page 12 , Final control diagnosis

un

pt
an
d
itte

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Checking voltage supply
erm

ab
ility
- -> Pull 2 pin connector -1- off valve -2-.
ot p

wit

- Connect multimeter to valve to measure resistance.

is n

h re

Specification: 25...35 ω
ole,

spec
urposes, in part or in wh

If the specification is not obtained:

t to the co

- Replace intake manifold change-over valve.

rrectness o
cial p

f inform
mer

atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
o
by c lksw
cted agen
Prote AG.

1.14 - Checking engine operating mode 45

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
Checking function

- Start engine and run at idling speed.

- -> Rev. up to 4000 rpm,
the vacuum unit -arrow- must switch over.

If the vacuum unit does not switch over:

- Check vacuum hose/pipe to vacuum unit and vacuum unit.

- Check at lever if shaft is free to move.

If the following conditions are fulfilled:

• Activation (final control diagnosis) OK.

• Vacuum hose/pipe and vacuum unit OK.
• Shaft free to move n AG. Volkswagen AG do
lkswage es n
o ot g
yV ua
- Renew intake manifold change-over valve (N156) => Page ir se 21 , item 5 .
d b ran
o tee
th or
au ac
ss

ce
le

1.16 - Checking air mass meter

un

pt
an
d
itte

y li
erm

ab
ility
ot p

Special tools, testers and auxiliary items

wit
is n

h re
ole,

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

spec
urposes, in part or in wh

◆ Test box V.A.G 1598/18

t to the co
◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
◆ Adapter set V.A.G 1594
◆ Current flow diagram

rrectne
Test conditions

ss
• Electrical consumers switched off (radiator fan must not run during the check)

o
cial p

f inform
mer

Checking voltage supply

atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

- -> Separate 3 pin connector to air mass meter.

- Connect multimeter to measure voltage at connector contacts 2+3.
- Switch on ignition
Specification: min. 11 V
- Switch off ignition.
- Reconnect connector.

If no voltage is present:

- Check wiring =>Page 47

46 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
n AG. Volkswagen AG do
lkswage Simos injection
es n and ignition system - Edition 11.1995
Vo ot g
by ua
ed ran
Test sequence or is tee
th or
au ac
s
- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
s

ce
le
word" 01. When doing this the engine must be running at idling speed.
un

pt
an
d
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)
itte

y li
rm

ab
pe

ility
-> Indicated on display:
ot

wit
, is n

Rapid data transfer HELP

h re
Select function XX
hole

spec
es, in part or in w

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

t to the co
-> Indicated on display:

rrectness of i
Read measured value block HELP
Input display group number XX
l purpos

- Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.

nform
ercia

-> Indicated on display:

m

a
(1...4 = Display zones)
com

tion in
r

Read measured value block 1

te o

thi
1 2 3 4

s
iva

do
r
rp

cum
fo

Only continue with the test when

en
ng

t.
yi Co
op py
• The coolant temperature is above 80 °C t. C rig
gh ht
-Display zone 2- yri
p by
co Vo
by lksw
cted agen
Prote
- Press C key.
AG.

- Press keys 0 and 3 for "Display group number 03" and confirm entry with Q key.

-> Indicated on display:

(1...4 = Display zones)
Read measured value block 3
1 2 3 4

- Check engine load signal in display zone 2:

Specification: 12...17 %

If the specification is not obtained:

- Check wiring =>Page 47

Checking wiring

- -> Connect test box V.A.G 1598/18 to control unit wiring loom -arrow-.

1.16 - Checking air mass meter 47

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

- -> Check wiring between test box and 3 pin connector for open circuit according to current flow diagram.
Contact 1+socket 14
Contact 2+socket 26
Wire resistance: Max. 1.5 ω
- Check wiring at 3 pin connector for short to one another according to current flow diagram.
Contact 3+socket 26
Contact 3+socket 14
Contact 2+socket 14
Specification: ∞ω

If no wiring fault is detected:

- Check wiring from contact 3 to current supply relay (J363).
- Check current supply relay (J363).

=> Current flow diagrams, Electrical fault finding and Fitting locations binder
If no wiring fault is detected and current supply relay is OK:
n AG. Volkswagen AG age does
o lksw not
- Renew air massd bmeter
yV (G70). gu
ara
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ris
utho eo
ra
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ss
1.17 - Checking throttle valve control part
ce
e
nl

pt
du

an
itte

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erm

ab

Note:
ility
ot p

wit
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If the throttle valve control part J338 is removed and installed or replaced the basic setting must be performed
h re
hole

=> Page 37 .
spec
es, in part or in w

t to the co

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
◆ Test box V.A.G 1598/18
rrectness of i

◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715

l purpos

◆ Adapter set V.A.G 1594

nform
mercia

at
om

ion
c

in t
or

his
ate

do
priv

cum
for

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

48 24 - Mixture preparation, Injection

 AG. Volkswagen AG d
agen
olksw Caddy 1996 , oPolo es n Classic 1996 ➤
ot g
yV
Simos isinjection
ed b and ignition system - Edition ua
ran 11.1995
or tee
th o
◆ Current flow diagram ss
au ra
c

ce
e
nl

pt
Checking voltage supply

du

an
itte

y li
erm

ab
- -> Separate 8 pin connector to throttle valve control part.

ility
ot p
- Connect multimeter using aux. cables from V.A.G 1594 to measure voltage at contacts 3+7 of connector.

wit
, is n
- Switch on ignition.

h re
Specification: 9.0...14.5 V

hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

orm
m

atio
om

n in
or c

thi
te

sd
iva

o
r
rp

cu
o

m
- Connect multimeter using aux. cables from V.A.G 1594 to measure voltage at contacts 4+7 of connector.
f

en
ng

t.
Specification: 4.0...6.0 V
yi Co
op
- Switch off ignition.
C py
t. rig
gh ht
pyri by
Vo
o
by c
If the specifications are not attained:
lksw
cted agen
Prote AG.

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.

- -> Check wiring between test box and 8 pin connector for open circuit according to current flow diagram.
Contact 3+socket 18
Contact 4+socket 41
Contact 7+socket 35
Wire resistance: Max. 1.5 ω
- Check wiring at 8 pin connector for short to one another.
Contact 7+socket 18
Contact 7+socket 41
Contact 4+socket 35
Specification: ∞ω

If no wiring fault is detected:

- Renew Simos control unit (J361)

=>Page 25 , item 9 .

Checking operating condition

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the ignition must be switched on.

1.17 - Checking throttle valve control part 49

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

-> Indicated on display:

Read measured value block HELP
Input display group number XX

- Press keys 0 and 7 for "Display group number 07" and confirm entry with Q key.
AG. Volkswagen AG d
-> Indicated on display: olksw
agen oes
not
(1...4 = Display zones) d by
V gu
ara
ise nte
Read measured value block 1 or eo
h
1 2 3 4
aut ra
ss c

ce
e
nl
- Check throttle valve control part operating condition in display zone 4.

pt
du

an
Specification: 00000000
itte

y li
erm

ab
ility
ot p

Relevance of figures in 8 digit number block for Lambda control and throttle valve control part.

wit
, is n

h re
hole

Significance when display position = 1

spec
es, in part or in w

x x x x x x x x Throttle valve control part operating condition (display group 07)

t to the co
1 Mechanical emergency running
1 Not relevant

rrectness of i
1 Adaptation required
l purpos

1 Adaptation required
1 Not relevant

nf
ercia

1 Adaptation terminated (battery voltage too low)

orm
1 Adaptation terminated (time exceeded)
m

atio
om

1 Idling speed switch open

n in
or c

thi
te

sd
a

If the specifications are not obtained:

iv

o
r
rp

cu
o

m
f

en
ng

- Perform basic setting => Page 37

t.
yi Co
op
- Repeat check. C py
t. rig
gh ht
pyri by
Checking idling switch
o Vo
by c lksw
cted agen
Prote AG.
- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the ignition must be switched on.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

-> Indicated on display:

Read measured value block HELP
Input display group number XX

- Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.

-> Indicated on display:

50 24 - Mixture preparation, Injection

 AG. Volkswagen AG d
agen oes
olksw not
byV gu
ara
rised
Caddy 1996 , Polo Classic 1996 nte ➤
o eo
Simos injection
aut
h
and ignition system - Edition 11.1995 ra
ss c

ce
(1...4 = Display zones)

le
un

pt
an
d
itte
Read measured value block 1

y li
rm
1 2 3 4

ab
pe

ility
ot

wit
- Check idling switch at idling stop in display zone 4.

, is n

h re
hole

spec
4th position from left must display 0

es, in part or in w
Display: 00000000

t to the co
- Slowly open throttle valve.

rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
iva

do
r
rp

cum
fo

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
o Vo
4th position from left must display 1 by c lksw
cted agen
Display: 00010000
Prote AG.

- Switch off ignition.

If the specifications are not obtained:

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
- With throttle valve closed connect multimeter to measure resistance at test box sockets 18+35.
Specification: max. 1.5 ω
- Slowly open throttle valve.
Specification: ∞ω

If the specifications are not obtained:

- -> Separate 8 pin connector to throttle valve control part.

- Check wiring between test box and 8 pin connector for open circuit according to current flow diagram.
Contact 3+socket 18
Contact 7+socket 35
Wire resistance: Max. 1.5 ω
- Check wiring at 8 pin connector for short to one another.
Contact 7+socket 18
Specification: ∞ω

If no wiring fault is detected:

1.17 - Checking throttle valve control part 51

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Replace throttle valve control part (J338).

Checking throttle valve potentiometer

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the ignition must be switched on.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
. Volkswage
n AG n AG d
wage oes
olks not
-> Indicated on display:
db
y V gu
ara
se
Read measuredorivalue block HELP nte
h eo
Input display
aut group number XX ra
ss c

ce
e

- Press keys 0 and 3 for "Display group number 03" and confirm entry with Q key.
nl

pt
du

an
itte

y li
-> Indicated on display:
erm

ab
ility
(1...4 = Display zones)
ot p

wit
, is n

Read measured value block 3

h re
1 2 3 4
hole

spec
es, in part or in w

- Read-off throttle valve angle in display zone 3.

Specification: 3.0...4.5 <° t to the co
- Slowly open throttle valve and watch angle display in display zone 3.
The figure must increase uniformly over
rrectness of i

the complete range.

- Press ⇒key.
l purpos

- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
- Switch off ignition.
nform
ercia

Note:
m

at
om

io

The displayed figure is dependent on the tolerances of the throttle valve potentiometer and does not correspond
n
c

in t
r

to the actual opening angle. The maximum permissible displayed figure is 99.5 <°.
o

his
ate

do
riv

If the figure does not increase uniformly:

p

cum
for

en
ng

- Replace throttle valve control part (J338).

t.
yi Co
Cop py
ht. rig
If the display shows constant 2 <°:
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
- Check wire for short to earth.
Sockets 01+40
Specification: ∞ω
- Switch ignition on.
- Check wire for short to positive, to do this connect multimeter to measure voltage at test box sockets 01+40
note voltage if voltage present

52 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Switch off ignition.

Continuation if voltage is present:

If voltage of about 5 V was present:

AG. Volkswagen AG d
agen oes
olksw not
y V gu
d b ara
rise nte
tho eo
au ra
ss c

ce
le
un

pt
an
d
itte

y li
rm

ab
pe

ility
ot

wit
, is n

h re
hole

- -> Separate 8 pin connector to throttle valve control part.

spec
- Switch ignition on.
es, in part or in w

t to the co
- Check wiring at 8 pin connector contacts 4+5 for short to one another according to current flow diagram.

If the voltage was approx. battery voltage:

rrectness of i
- Check wire at 8 pin connector contact 5 for short to battery positive according to current flow diagram.
l purpos

Continuation if no voltage is present:

nform
mercia

a
com

tion in
r
te o

thi
s
iva

do
r
rp

cum
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

- -> Separate 8 pin connector to throttle valve control part.

- Check wiring between test box and 8 pin connector for open circuit according to current flow diagram.
Contact 5+socket 40
Wire resistance: Max. 1.5 ω

If no wiring fault is detected:

- Replace throttle valve control part (J338).

Checking throttle valve positioner and throttle valve positioner potentiometer

Test conditions

• Coolant temperature at least 80 °C

Test sequence

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the engine must be running at idling speed.

1.17 - Checking throttle valve control part 53

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display: AG. Volkswagen AG d

agen oes
Rapid data transfer HELP olksw not
Select function XX byV gu
ara
ed
ris nte
ho eo
ut
- Press keys 0 and 8 for thessfunction "Read measured value block" and confirm
a ra
c entry with Q key.

ce
e
nl

pt
-> Indicated on display:
du

an
itte

y li
Read measured value block HELP
erm

ab
Input display group number XX

ility
ot p

wit
, is n

- Press keys 0 and 3 for "Display group number 03" and confirm entry with Q key.

h re
hole

spec
-> Indicated on display:
es, in part or in w

t to the co
(1...4 = Display zones)
Read measured value block 3
1 2 3 4

rrectness of i
- Check throttle valve positioner duty cycle at idling speed stop in display zone 4.
l purpos

Specification: 13...20 %

nf
ercia

If the specification is not obtained:

orm
m

atio
om

n in
or c

thi
te

sd
iva

o
r
rp

cu
o

m
f

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
co Vo
by lksw
cted agen
Prote AG.

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
- With throttle valve closed connect multimeter to measure resistance at test box sockets 25+30.
Specification: 3...200 ω

If the specification is not obtained:

- -> Separate 8 pin connector to throttle valve control part.

- Check wiring between test box and 8 pin connector for open circuit according to current flow diagram.
Contact 1+socket 30
Contact 2+socket 25
Contact 7+socket 35
Contact 8+socket 28

54 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
Volkswagen AG
Wire resistance: Max.sw
1.5
ageω
n AG. does
olk not
yV gu
edb ara
ris nte
tho eo
au ra
c
ss

ce
le
un

pt
an
d
itte

y li
erm

ab
ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectne
- -> Check wiring at 8 pin connector for short to one another.
Contact 1+socket 25
Contact 1+socket 28

ss
Contact 1+socket 35

o
cial p

f i
Contact 2+socket 28

nform
Contact 2+socket 35
mer

Contact 7+socket 28

atio
m

Specification: ∞ω
o

n
c

i
or

n thi
te

sd
If no wiring fault is detected:
iva

o
pr

cum
r
fo

- Replace throttle valve control part (J338).

en
ng

t.
yi Co
Cop py
ht. rig
rig ht
py by
o Vo
1.18 - Checking coolant temperature sender by c lksw
cted agen
Prote AG.

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
◆ Test box V.A.G 1598/18
◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
◆ Adapter set V.A.G 1594
◆ Current flow diagram

Test conditions
• Engine cold

Test sequence
- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the engine must be running at idling speed.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

-> Indicated on display:

Read measured value block HELP
Input display group number XX

- Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.

-> Indicated on display:

1.17 - Checking throttle valve control part 55

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
(1...4 = Display zones)
Read measured value block 1
1 2 3 4

Functional check of sender

- Observe coolant temperature figure in display zone 2. The temperature figure must
Increase uniformly and without interruption.

If a temperature figure is displayed which deviates greatly from the senders ambient temperature, check
sender wiring for transfer resistances.

Notes:

◆ Depending upon the temperature level, the display on faultVreader will jump by 2...5 °C
◆ If irregular engine running occurs in certain temperature AG. olkand
genranges
swagen AG
the temperature
does figure does not increase
wa
ks
without interruption, the temperature signal is by temporarily interrupted and the sender
Vol
not
gu
a
must be renewed.
ed ran
ris tee
- Press ⇒key. tho or
au ac
- Press keys 0 and 6 for the function "End
ss output" and confirm entry with the Q key.

ce
le
un

pt
an
d
itte

y li
erm

ab
ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectness o
cial p

f inform
mer

If the figure does not increase uniformly:

atio
om

n
c

- Replace coolant temperature sender -2-.

i
or

n thi
te

sd
va

If a G62 fault is indicated in fault memory even though the figure increases uniformly:
i

o
pr

cum
r
fo

en
ng

- Switch off ignition.

t.
yi Co
op
- -> Connect test box V.A.G 1598/18 to control unit wiring loom. C py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

- -> Pull 4 pin connector -1- of coolant temperature sender (G62) -2-.

56 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

- -> Check wiring between test box and 4 pin connector for open circuit according to current flow diagram.
Contact 1+socket 35
Contact 3+socket 12
Wire resistance: Max. 1.5 ω
- Check wire between control unit connector
AG. Volkswagenand
AG 4 pin connector contact 3 for short to wire contact 1 and to
vehicle earth, accordingolkto agen
swcurrent flow diagram.does not
Sockets 12 + 35 db
yV gu
ara
Specification: r se
i∞ω nte
ho eo
- Additionally scheck
aut
wires for short to battery positive. ra
c
Specification:
s ∞ω

ce
le
un

pt
an
d

If no fault in wire is detected:

itte

y li
rm

ab
pe

ility
- Perform resistance measurement at coolant temperature sender (G62) contacts 1+3, resistance figures =>
ot

wit
Page 35 , Fig. 1
, is n

h re
hole

spec
If the specification is not obtained:
es, in part or in w

t to the co
- Renew coolant temperature sender (G62) => Page 27 , item 23 . rrectness of i

1.19 - Checking intake air temperature sender

l purpos

nform
ercia

Special tools, testers and auxiliary items

m

a
com

tio

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
n in
r

◆ Test box V.A.G 1598/18

te o

thi

◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715

s
iva

do

◆ Adapter set V.A.G 1594

r
rp

cum
fo

◆ Current flow diagram

en
ng

t.
◆ Chilling spray (commercially available)
yi Co
Cop py
t. rig
gh ht
yri
Test sequence p by
co Vo
by lksw
cted agen
Prote AG.
- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the ignition must be switched on.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP
Select function XX

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

-> Indicated on display:

Read measured value block HELP
Input display group number XX

1.18 - Checking coolant temperature sender 57

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Press keys 0 and 2 for "Display group number 02" and confirm entry with Q key.

-> Indicated on display: AG. Volkswagen AG d

agen oes
ksw
(1...4 = Display zones) by Vol not
gu
d ara
Read measured value block 2 rise nte
1 2 3 4 tho eo
au ra
ss c

ce
le
Functional check of sender
un

pt
an
d
itte

y li
rm

- Note intake air temperature figure in display zone 4.

ab
pe

ility
ot

wit
, is n

Display Cause Continuation of

h re
check
hole

spec
approx. 20 °C Open circuit or => Page 58
es, in part or in w

t to the co
short to positive
Short to earth
Approx. ambient --- => Page 59

rrectness of i
temperature1)
l purpos

1) If a temperature is displayed which deviates greatly from the ambient temperature of the sender, check
sender wiring for transfer resistances.

nform
mercia

a
Continuation of check when display approx. 20 °C:
com

tion in
r
te o

- Switch off ignition.

thi
s
iva

do
r
rp

cum
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.

- -> Pull 2 pin connector -1- off intake air temperature sender (G42) -2-.

58 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

AG. Volkswagen AG d
agen oes
olksw not
V gu
d by ara
ise nte
or eo
h
aut ra
ss c

ce
e
nl

pt
du

an
itte

y li
erm

ab
ility
ot p

wit
, is n

h re
- -> Check wiring between test box and 2 pin connector for open circuit according to current flow diagram.
hole
Contact 1+socket 37

spec
Contact 2+socket 35
es, in part or in w

t to the co
Wire resistance: Max. 1.5 ω
- Check wire between control unit connector and 2 pin connector contact 2 for short to wire contact 1 and to
vehicle earth, according to current flow diagram.

rrectness of i
Contact 2+socket 37
Specification: ∞ω
l purpos

- Additionally check wiring for short to battery positive.

Specification: ∞ω

nf
ercia

o
If no fault in wire is detected:

rm
m

atio
om

n in
- Perform resistance measurement on intake air temperature sender (G42) contacts 1+2, resistance figures
or c

=> Page 35 , Fig. 1

thi
te

sd
iva

o
r
rp

cu
If the specification is not obtained:
o

m
f

en
ng

t.
yi Co
- Renew intake air temperature sender (G42) Cop py
t. rig
=>Page 22 , item 15 . gh ht
pyri by
Vo
o
by c lksw
cted
Continuation of check when display = ambient temperature:
agen
Prote AG.

- -> Remove intake air temperature sender G42) (plug remains connected).
- Note intake air temperature figure in display zone 4.
- Spray sender with a commercial chilling spray and at the same time observe the temperature figure. The
temperature figure must
decrease.
- Press ⇒key.
- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

1.19 - Checking intake air temperature sender 59

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.20 - Checking engine speed sender

Special tools, testers and auxiliary items

◆ Test box V.A.G 1598/18

◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
◆ Adapter set V.A.G 1594
◆ Current flow diagram

Test sequence

- -> Detach 3 pin connector to sender -1-.

- Switch ignition on.

AG. Volkswagen AG d
agen oes
olksw not
V gu
d by ara
ise nte
or eo
h
aut ra
ss c
ce
e
nl

pt
du

- -> Check voltage between contacts 1+3 of detached connector.

an
itte

y li

Specification: Min. 9 V
erm

ab

- Switch off ignition.

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spec
es, in part or in w

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rrectness of i
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nform
mercia

at
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c

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or

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
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ate

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for

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60 24 - Mixture preparation, Injection
AG.
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

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- -> Check wiring between test box and 3 pin connector for open circuit according to current flow diagram.

wit
, is n

Contact 1+socket 68

h re
hole

Contact 2+socket 67

spec
Contact 3+socket 16
es, in part or in w

t to the co
Wire resistance: Max. 1.5 ω
- Additionally check wires for short to one another.
Contact 1+socket 67
Contact 1+socket 16

rrectness of i
Contact 2+socket 16
l purpos

Specification: ∞ω

If no wiring fault is detected and voltage was present between contacts 1+3:

nform
mercia

- Replace engine speed sender (G28).

at
om

ion
c

in t
r

If no wiring fault is detected and no voltage was present between contacts 1+3:
o

his
ate

do
riv

- Renew Simos control unit (J361)

p

cum
or

=>Page 25 , item 9 .
f

en
ng

t.
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Cop py
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1.21 - Checking speed signal by c lksw
cted agen
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Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
◆ Adapter set V.A.G 1594
◆ Current flow diagram

Test conditions

• Speedometer OK., checking:

=> Repair group 90, Electrical system

Note:
To check the speed signal the vehicle must be driven. To do this a second person is necessary.
Test sequence

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the engine must be running at idling speed.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP
Select function XX

1.20 - Checking engine speed sender 61

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

-> Indicated on display:

Read measured value block HELP
Input display group number XX

- Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.

-> Indicated on display:

(1...4 = Display zones)
Read measuring value block 4
1 2 3 4

- Carry out test drive and when doing this observe display (2nd person necessary).
- Observe displayed figure in display zone 3:
Specification: approx. driven speed
- Press ⇒key.
- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

If no speed is indicated:

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- -> Detach 3 pin connector from sender -1-.

es, in part or in w

- Switch ignition on.

t to the co
rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
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en
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t.
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- -> Check voltage between contacts 1+3 of detached connector.
t. C rig
gh ht
Specification: Min. 9 V pyri by
Vo
co
- Switch off ignition.
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- Reconnect connector
AG.

If no voltage was present:

- Check wiring according to current flow diagram.

If the specification is attained:

62 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
- Connect multimeter to measure voltage at sockets 1+11.
- Switch ignition on.
- Raise left front wheel or push vehicle. The voltage figure must fluctuate between
0...at least 4 V.

If no wiring fault is detected and voltage was present between contacts 1+3:

- Renew Simos control unit (J361)

=>Page 25 , item 9 .

If the specification is not obtained:

- Check for wiring open circuit according to current flow diagram, if necessary replace speedometer sender
(G22).

1.22 - Checking control unit voltage supply

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Special tools, testers and auxiliary uitems
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◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
ce
le
un

pt

◆ Test box V.A.G 1598/18

an
d
itte

◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715

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erm

ab

◆ Adapter set V.A.G 1594

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◆ Current flow diagram

wit
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Check conditions
spec
urposes, in part or in wh

t to the co

• Battery voltage at least 11 V

• Alternator OK
rrectne

Test sequence

Checking voltage supply via relay (J363)

ss o
cial p

f i

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
nform

word" 01. When doing this the engine must be running at idling speed.
mer

atio

(Connecting fault reader and selecting engine electronics control unit => Page 2 .)
om

n
c

i
or

-> Indicated on display:

thi
te

sd
iva

Rapid data transfer HELP

pr

cum
r

Select function XX
fo

en
ng

t.
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op
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key. C py
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-> Indicated on display: by c lksw
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1.21 - Checking speed signal 63

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Read measured value block HELP

Input display group number XX

- Press keys 0 and 2 for "Display group number 02" and confirm entry with Q key.

-> Indicated on display:

(1...4 = Display zones) agen
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Read measured value block 2
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- Read off figure displayed in display zone 3. ss

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Specification: approx. battery voltage constant

nl

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- Press ⇒key.

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itte

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- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
erm

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If the displayed figure fluctuates or the battery voltage is not attained:

wit
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hole

spec
- Switch off ignition.
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

orm
m

atio
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or c

thi
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sd
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f

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- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
t.
yi Co
op
- Switch ignition on. C py
ht. rig
- Check supply voltage with multimeter and aux. cables from V.A.G 1594 between the test box sockets 1+8: rig ht
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Specification: Min. 9 V
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- Check voltage with multimeter and aux. cables from V.A.G 1594 between test box sockets 1+23:
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Specification: Min. 11 V

If the specifications are not attained:

- Replace voltage supply relay (J363).

Checking voltage supply terminal 15

Test conditions

• Fuse 15 OK

- Check voltage supply with multimeter and aux. cables from V.A.G 1594 between test box sockets 1+38:
Specification: Min. 11 V

If the specification is not obtained:

- Check wiring according to current flow diagram.

64 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.23 - Matching engine electronic control unit to electronic immobilizer

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3

Test conditions

• Authorized vehicle key required

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rrectness of i
- -> Fold driver's side stowage compartment down.
l purpos

- Connect fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3.
- Switch on ignition.
- Operate fault reader or vehicle system tester taking into account the information on the display:
nform
ercia

- Press key 1 for "Rapid data transfer".

- Press keys 2 and 5 for address word "Immobilizer" and confirm entry with Q key.
m

at
om

- Press the ⇒key.

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c

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his
e

-> Indicated on display:

at

do
priv

Rapid data transfer HELP

um
for

Select function XX
en
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- Press keys 1 and 0 for function "Adaption" and confirm entry with Q key.
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-> Indicated on display: cted agen
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Adaption
Feed in channel number XX

- Press key 0 twice for "Channel number 0" and confirm entry with Q key.

-> Indicated on display:

Adaption Q
Erase learnt values?

- Confirm input with Q key.

-> Indicated on display:

Adaption
Learnt values have been erased

- Conclude adaption by pressing ⇒ key.

- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
- Switch off ignition.

1.23 - Matching engine electronic control unit to electronic immobilizer 65

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
Note:
The identity of the engine control unit is read into the immobilizer control unit when next switching the ignition
on.

1.24 - Checking air conditioner and air conditioner compressor signals

Special tools, testers and auxiliary items
◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
◆ Test box V.A.G 1598/18
◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
◆ Adapter set V.A.G 1594
◆ Current flow diagram

Check conditions
• Function of air conditioner OK.
• Air conditioner switched off
• Interior of vehicle has room temperature (above 15 ° C)
• No faults stored in fault memory
=> Page 4 , interrogating fault memory

Test sequence
- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
word" 01. When doing this the engine must be running at idling speed.
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

Rapid data transfer HELP
Select function XX
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

-> Indicated on display: agen

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Input display group d bynumber XX ara
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- Press keys aut0 and 1 for "Display group number 01" and confirm
h eo
ra entry with Q key.
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-> Indicated on display:

un

pt

(1...4 = Display zones)

an
d
itte

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erm

ab

Read measured value block 1

ility

1 2 3 4
ot p

wit

- Observe 8 digit number block in display zone 4. 3rd position from left must display 0.
is n

h re

Display: 00000000
ole,

spec

- Switch on air conditioner. Adjust lowest temperature and highest blower stage.
urposes, in part or in wh

t to the co

3rd position from left must now display 1

Display: 00100000
rrectne

If the display does not change:

ss o
cial p

f inform
mer

atio
om

n
c

i
or

n thi
te

sd
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pr

cum
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fo

en
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t.
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Cop py
t. rig
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pyri by
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by c lksw
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Prote AG.

66 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
- Check wiring between test box sockets 13 and 39 and the air conditioner for open circuit according to current
flow diagram.
Wire resistance: Max. 1.5 ω
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1.25 - Checking starterutsignal
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Special tools, testers and auxiliary items

an
d
itte

y li
erm

ab
◆ Test box V.A.G 1598/18

ility
ot p

wit
is n

h re
ole,

spec
urposes, in part or in wh

t to the co
rrectness o
cial p

f inform
mer

atio
om

n
c

i
or

n thi
◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
te

sd
a

◆ Adapter set V.A.G 1594

iv

o
pr

c
◆ Current flow diagram

um
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fo

en
ng

t.
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Test sequence C py
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- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
co Vo
by lksw
cted
- Connect multimeter to measure voltage at test box sockets 1+32.
agen
Prote AG.
- Operate starter. Multimeter must indicate
min. 8 V.

If the specification is not obtained:

- Check wiring to starter terminal 50 according to current flow diagram.

1.26 - Checking injectors

Special tools, testers and auxiliary items

◆ Test box V.A.G 1598/18

◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
◆ Diode test lamp V.A.G 1527
◆ Adapter set V.A.G 1594
◆ Current flow diagram

Check conditions

• Engine speed sender OK.

• Fuel pump relay OK

Checking activation

- Remove intake manifold upper part, => Page 31 , item 8 .

1.24 - Checking air conditioner and air conditioner compressor signals 67

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

- -> Pull plug -1- off connection -2- and connect diode test lamp V.A.G 1527 with aux. cables from V.A.G 1594
to the contacts of the plug.
- Pull the connectors off injectors 2...4.
- Operate starter and check the voltage supply for No. 1 Cyl. injector.
LED must flicker
- Repeat check on injectors 2...4.

The LED does not flicker:

- Switch off ignition.

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ility
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wit
is n

h re
ole,

spec
urposes, in part or in wh

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
t to the co
rrectness o
cial p

f inform
mer

atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
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op
- -> Check wiring between test box and connector for open circuit according to current flow diagram.
C py
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Injector 1: Contact 2+socket 02 gh ht
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Injector 2: Contact 2+socket 46 cop Vo
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Injector 3: Contact 2+socket 47
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Injector 4: Contact 2+socket 48
Wire resistance: Max.1.5 ω
- Check wiring between connector for injectors contact 1 and relay plate for open circuit according to current
flow diagram.
Wire resistance: Max. 1.5 ω
- Additionally check wires for short to one another.

68 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
Specification: ∞ω

Checking resistance of injectors

- -> Check resistance of injectors individually

Specification: 15...20 ω

If the specification is not attained, replace injector(s) as necessary.

Checking spray pattern and for leaks
Warning!
The fuel system is pressurized! Before loosening hose connections or opening the test connection, wrap a cloth
around the connection. Then release pressure by carefully pulling off the hose/sealing cap.
Special tools, testers and auxiliary items
◆ Adapter set V.A.G 1594
◆ Digital potentiometer V.A.G 1630
◆ Measuring unit V.A.G 1602

Test sequence AG. Volkswagen AG d

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pe

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hole

spec
es, in part or in w

t to the co

- Remove intake manifold upper part, => Page 31 , item 8 .

- Remove fuel manifold complete with injectors => Page 21 , Item 3 .
rrectness of i

- -> Hold injectors in the measuring appliance V.A.G 1602.

l purpos

nform
mercia

a
com

tion in
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thi
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rp

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fo

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t.
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Cop py
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rig ht
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1.26 - Checking injectors 69

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- -> Pull plug off coolant temperature sender (G62).
- Set digital potentiometer V.A.G 1630 -side A- to 15 kωand using aux. cables from V.A.G 1594 connect to
contacts 1+3 of disconnected plug.
- Pull plug off ignition transformer.
- Operate starter (2nd person required). The injectors must pulsate and spray in accordance with firing order.
- Switch off ignition and check injectors for leaks. No more than
2 drops/min
may leak from each injector.

Note:

When installing the injectors ensure that the O rings

are not damaged.

1.27 - Checking fuel pressure regulator and holding pressure

The fuel pressure regulator controls the fuel pressure dependent upon intake manifold pressure.

The specifications are dependent upon the fuel pump working pressure. This is
approx. 4 bar

Special tools, testers and auxiliary items

◆ Pressure tester V.A.G 1318

◆ Adapter 1318/10
◆ Adapter 1318/11 agen
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◆ Adapter 1318/16 olksw not
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Test sequence ut
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un

Warning!
pt
an
d
itte

The fuel system is pressurized! Before loosening hose connections or opening the test connection, wrap a cloth
y li
rm

ab

around the connection. Then release pressure by carefully pulling off the hose/sealing cap.
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ility
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hole

spec
es, in part or in w

t to the co
rrectness of i
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nform
mercia

a
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tion in
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- -> Pull fuel supply pipe -1- off fuel manifold connection -2- and connect to pressure gauge V.A.G 1318 using
thi
s
iva

adapter 1318/10.
do
r
rp

- Connect pressure gauge V.A.G 1318 to fuel manifold -2- using adapter 1318/11 and 1318/16. Open pressure
um
fo

gauge cut-off tap (handle in throughflow direction -arrow-).

en
ng

t.
yi
- Start the engine and run at idling speed.
Co
Cop py
- Check fuel pressure. ht. rig
rig ht
Specification: Approx. 2.5 bar
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If the specification is not obtained:

- Check quantity supplied by fuel pump.

70 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

AG. Volkswagen AG d
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ole,

spec
urposes, in part or in wh

t to the co
=> Rep. Gr. 20; Removing and installing parts of fuel system; checking fuel pump

If the specification is attained:

rrectne
- -> Pull vacuum hose - 1- off connection -2-. The fuel pressure must rise to

ss
approx. 3.0 bar.

o
cial p

f
- Switch off ignition.

inform
- Check for leaks and holding pressure by observing pressure drop on gauge. After 10 minutes there must
mer

be

atio
m

a residual pressure of
o

n
c

i
at least 2.0 bar.
or

n thi
te

sd
iva

o
If the holding pressure drops below 2 bar:
pr

cum
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fo

en
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t.
- Start the engine and run at idling speed.
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When the fuel pump has built-up the pressure again: py by
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- Switch off ignition and use a second mechanic to seal the return pipe -with blue marking- on fuel manifold
AG.

with a clamp.
- Watch pressure drop on gauge.

If the pressure does not drop:

- Renew fuel pressure regulator => Page 22 , item 19 .

If the pressure drops again:

- Check pressure gauge for leaks.

- Check pipe connections, O rings on fuel manifold and injectors for leaks.
- Check fuel pump non-return valve:

=> Rep. Gr. 20; Removing and installing parts of fuel system; checking fuel pump

When the pressure gauge is removed after completing the test:

1.27 - Checking fuel pressure regulator and holding pressure 71

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- Switch off ignition.
- Hold a measuring container before the pressure gauge cut-off tap.
- -> Open pressure gauge cut-off tap -arrow- carefully and release pressure.

1.28 - Checking intake air system for leaks (unmetered air)

Checking with engine leak detector spray G 001 800 A1

Special tools, testers and auxiliary items

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with. Vcable V.A.G 1551/3
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◆ Engine leak detector spray G 001 800 A1 ksw
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Notes: se ran
ri tee
ho
aut or
ac
◆ The vacuum in the intake system will causessthe leak detector
spray to be drawn in with the outside air. The

ce
le

leak detector spray reduces the ignitability of the mixture. This leads to a drop in engine speed and to a
un

pt
an
significant increase of the CO content.
d
itte

y li
◆ The safety precautions listed on the container must be adhered to.
rm

ab
pe

ility
ot

Test sequence

wit
, is n

h re
hole

spec
- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
es, in part or in w

word" 01. When doing this the engine must be running at idling speed.

t to the co
(Connecting fault reader and selecting engine electronics control unit => Page 2 .)

-> Indicated on display:

rrectness of i
Rapid data transfer HELP
l purpos

Select function XX

- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

nform
mercia

-> Indicated on display:

a
com

tion in
Read measured value block HELP
r
te o

thi
Input display group number XX

s
iva

do
r
rp

c
- Press keys 0 and 1 for "Display group number 01" and confirm entry with Q key.
um
fo

en
ng

t.
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-> Indicated on display: C py
t. rig
(1...4 = Display zones) gh ht
pyri by
Vo
co lksw
Read measured value block 1 cted
by agen
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- Note engine speed in display zone 1.

- Note Lambda probe voltage in display zone 3 and the area it fluctuates in.
- Systematically spray parts of the intake system with engine leak detector spray.

Engine speed or Lambda probe voltage does not change:

- Press the ⇒key.

- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

If the engine speed drops or the Lambda probe voltage changes:

- Press the ⇒key.

- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.
- Check sprayed areas of intake system for leaks and rectify if necessary.

72 24 - Mixture preparation, Injection

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

28 - Ignition system

1 - Simos injection and ignition system

1.1 - Simos injection and ignition system

1.2 - Servicing ignition part

Notes:

◆ Only the components which specifically relate to the ignition system are dealt with here. For the other com‐
ponents of the injection and ignition system

=> Repair group 24 AG. Volkswagen AG d

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olksw not
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◆ The injection and ignition system control unit is equipped
ed by with self diagnosis. gu
ara
◆ Components marked with a * are checked via tthe ho self diagnosis.
ris nte
eo
◆ Before carrying out repairs and for fault finding,
s au interrogate fault memory => Page 4 , interrogating ra
c and
erasing fault memory s

ce
le

◆ During some checks it is possible that the control unit will recognise and store a fault. Therefore after com‐
un

pt
an
d

pleting all checks and repairs the fault memory must be interrogated and if necessary erased.
itte

y li
=> Page 4 , interrogating fault memory
rm

ab
pe

ility
ot

wit
Safety precautions => Page 77
, is n

h re
hole

spec
Test data, spark plugs => Page 77
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

a
com

tion in
r
te o

thi
s
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cum
fo

en
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Cop py
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1.1 - Simos injection and ignition system 73

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

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urposes, in part or in wh

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Note:
rrectne

Simos control unit (J361)* with connector => Page 20 , item 8

ss o

1 H.T. cable
cial p

f in

◆ Check for continuity

form
mer

2 Suppressor
atio
m

◆ 0.6...1.4 kω
o

n
c

i
or

3 10 Nm
thi
te

sd
va

4 Ignition transformer (N152)

i

o
pr

cum
r

◆ With output stage (N157)

fo

en
ng

◆ Checking => Page 85

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5 Connector
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◆ 3 pin copy Vo
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6 Earth strap
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7 Knock sensor 1 (G61)*

◆ Checking => Page 83

74 28 - Ignition system
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

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nl

pt
du

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itte

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erm

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ility
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wit
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hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

at
om

ion
c

in t
or

his
ate

do
priv

cum
for

en
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t.
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8 3 pin connector
◆ Blue
9 20 Nm
◆ Tightening torque influences the function of the knock sensor
10 Spark plug connector
◆ 4...6 kω
11 Spark plug, 30 Nm
◆ Type and electrode gap
=> Page 77 , test data, spark plugs
12 25 Nm
13 Clamp
14 O ring
◆ Renew if damaged

1.2 - Servicing ignition part 75

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

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es, in part or in w

t to the co
rrectness of i
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nform
ercia

15 Distributor with Hall sender (G40)*

m

a
com

ti

◆ Removing and installing => Page 78

on in

◆ Checking Hall sender

r
te o

thi

=> Page 82
s
iva

do
r

16 Dust cap
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cum
fo

17 Rotor arm
en
ng

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op
◆ Marking: R1 C py
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◆ 0.6...1.4 kω
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18 Distributor cap
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◆ Check for cracks and signs of tracking
AG.

◆ Check contact wear

◆ Clean before fitting
◆ Check carbon brush for wear and freedom of movement
19 Screening cap

76 28 - Ignition system
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.3 - Safety precautions

To prevent injuries to persons and/or damage to the injection and ignition system, the following must be ob‐
served:

◆ Do not touch or pull off ignition wiring when engine is running or turning at starter speed.
◆ The ignition must be switched off when disconnecting or connecting injection and ignition system wiring as
well as test instrument cables.
◆ If the engine is to be turned at starter speed, without starting, e.g. when checking compressions, pull 3 pin
connector off ignition transformer.

1.4 - Test data, spark plugs

Engine code AFT

Ignition timing1)
Checking position of distributor =>Page 77
Checking ignition timing control =>Page 82
Ignition timing 1-3-4-2
Spark plugs2)
VW/Audi 101 000 033 AC
Manufacturer's designation BKUR 5 ET
Electrode gap AG. Volkswagen AG d0.7...0.9 mm
agen oes
Tightening torque yV
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1) Not adjustable au
tho
or
ac
ss

ce
le

2) Up-to-date specifications:
un

pt
an
d
itte

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=> Exhaust emissions test binder
erm

ab
ility
ot p

wit
is n

h re
ole,

1.5 - Checking position of distributor

spec
urposes, in part or in wh

t to the co
Note:

rrectne
The position of the distributor does not influence the ignition timing.
s
Special tools, testers and auxiliary items
s o
cial p

f inform

◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
mer

atio
m

Test sequence
o

n
c

i
or

n thi
e

- Connect fault reader V.A.G 1551 (V.A.G 1552) and select engine electronics control unit with the "Address
t

sd
iva

word" 01. When doing this the engine must be running at idling speed.
pr

cum
r
fo

(Connecting fault reader and selecting engine electronics control unit => Page 2 .)
en
ng

t.
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op py
-> Indicated on display: t. C rig
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Rapid data transfer HELP by c
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Select function XX cted agen
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- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

-> Indicated on display:

1.3 - Safety precautions 77

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

Read measured value block HELP

Input display group number XX

- Press keys 0 and 7 for "Display group number 07" and confirm entry with Q key.

-> Indicated on display:

(1...4 = Display zones)
Read measured value block 1
1 2 3 4

- Read off figure displayed in display zone 1.

Specification: 57...60 or 1
- Read off figure displayed in display zone 2.
Specification: 5...8
- Press ⇒key.
- Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

If the specifications are not attained:

- Check alignment of TDC marks on distributor => Page 78 , removing and installing distributor

If the TDC marks align:

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- -> Pull out pins on distributor (if fitted) and turn distributor until the specifications in display zones 1 and 2
wit
, is n

are achieved.
h re
hole

spec
es, in part or in w

t to the co

1.6 - Removing and installing distributor

rrectness of i

Special tools, testers and auxiliary items

l purpos

◆ Pin wrench Matra V159

◆ Torque wrench V.A.G 1331 (5 - 50 Nm)
nform
ercia

Note:
m

The Simos control unit requires the No. 1 cylinder TDC signal from the Hall sender to coordinate the injection
a
com

tio

and knock sensor systems according to the firing order.

n in
r
te o

Checking No. 1 cylinder TDC markings:

thi
s
iva

do
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rp

cum
fo

en
ng

t.
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Cop py
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78 28 - Ignition system
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
- -> Set flywheel -A- or drive plate -B- to TDC No. 1 cylinder.
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urposes, in part or in wh

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Engine removed

- -> Set vibration damper (V-belt pulley) to TDC No. 1 cylinder.

ss o
cial p

f inform
mer

atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
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- -> Mark on camshaft sprocket must align with arrow on cylinder head.

- -> Mark on distributor must align with mark on rotor arm or Hall sender cover.

Removing and installing distributor

Test conditions

• Crankshaft and camshaft in No. 1 cylinder TDC position

1.6 - Removing and installing distributor 79

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

- -> Before installing the distributor align oil pump shaft drive tongue parallel to crankshaft.

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- -> Install distributor. The pins on the distributor must point towards securing bolt threaded hole -arrow-.

ce
e
nl

pt
du

an
itte

Note:

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erm

ab
ility
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When installing, turn rotor arm slightly right of the distributor marking. When inserting the rotor arm will turn

wit
, is n

back onto the marking.

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hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

at
om

ion
c

in t
or

his
ate

do
riv

- -> Mark on distributor must align with mark on rotor arm or Hall sender cover.
p

cum
or

- Tighten distributor securing bolt.

f

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ng

t.
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Tightening torque: 25 Nm
Co
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If no alignment of the markings can be achieved: p by
co Vo
by lksw
cted agen
Prote AG.
- Loosen tensioning roller and take toothed belt off camshaft sprocket.

80 28 - Ignition system
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

- -> Turn intermediate shaft sprocket with toothed belt so long in direction of arrow until rotor arm aligns with
markings for No. 1 cylinder on distributor housing (toothed belt slides over crankshaft sprocket).

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• -> Mark on distributor must align with mark onut rotor arm or Hall sender cover.
h o eo
ra
s a c
s
- Place toothed belt on tensioning roller and camshaft sprocket.

ce
le
un

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itte

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Note:
erm

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ility
ot p

For easier installation of the toothed belt loosen tensioner roller lock nut only approx. one thread.

wit
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ole,

spec
urposes, in part or in wh

t to the co
rrectness o
cial p

f inform
mer

atio
om

n
c

i
or

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sd
a

- -> Tension toothed belt, to do this turn tensioner with pin wrench (e.g. Matra V159) in direction of arrow.
iv

o
pr

cum
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fo

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ng

It must just be possible to turn the toothed belt through 90° with the thumb and forefinger in the centre between
t.
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camshaft and intermediate shaft sprockets. Cop py
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- Tighten tensioner lock nut.
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Tightening torque: 45 Nm
agen
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- Rotate crankshaft two full turns and check adjustment.
- Check distributor housing and rotor arm markings.
- Install upper toothed belt protective cover.
- Before fitting, clean distributor cap and check for cracks and signs of tracking, renew if necessary.

1.6 - Removing and installing distributor 81

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

1.7 - Checking ignition timing control

Special tools, testers and auxiliary items

◆ Ignition tester V.A.G 1767 or V.A.G 1367 with HT pick-up clamp V.A.G 1367/8

Check conditions
• No fault stored in fault memory
• Engine oil temperature at least 80 °C

Test sequence

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-> Connect ignition tester V.A.Goris1767 or ignition tester V.A.G 1367 with rHT an pick-up clamp V.A.G 1367/8.
tee
- Start engine and run at idlingauspeed.
th or
ac
- Set ignition tester to 4000 rpm.
ss
- Slowly increase speed to slightly above 4000 rpm until the ignition timing (advance figure) is displayed.

ce
e
nl

pt
du

Specification: 25...35 ° before TDC

an
itte

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erm

ab
If the specification is not obtained:
ility
ot p

wit
- Renew Simos control unit (J361)
, is n

h re
=>Page 25 , item 9 .
hole

spec
es, in part or in w

t to the co

1.8 - Checking Hall sender

rrectness of i

Special tools, testers and auxiliary items

l purpos

◆ Test box V.A.G 1598/18

◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
◆ Adapter set V.A.G 1594
nf
ercia

◆ Current flow diagram

rm
m

atio
om

Test conditions
n in
or c

thi

• Sender fault is recognised by self diagnosis

te

sd
iva

o
r
rp

cu

Test sequence
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f

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t.
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Cop py
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cted agen
Prote AG.

82 28 - Ignition system
 Caddy 1996 , Polo Classic 1996 ➤
Simos
olksw
injection and ignition system - Edition 11.1995
.V agen AG
gen AG does
swa
- Pull plug off sender
y V (distributor).
olk not
gu
- edb
-> Connect rimultimeter to measure voltage with aux.ara
cables from V.A.G 1594 to the outer contacts of the
s nte
plug. utho eo
ra
- Switchsson ignition.
a c
Specification: At least 10 V

ce
e
nl

pt
- Switch off ignition.
du

an
itte

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erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
mercia

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.

at
om

ion
c

in t
or

his
ate

do
priv

cum
for

en
ng

t.
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Cop py
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- -> Check wiring between test box and 3 pin connector for open circuit according to current flow diagram.
Contact 1+socket 35
Contact 2+socket 44
Contact 3+socket 45
Wire resistance: Max. 1.5 ω
- Additionally check wires for short to one another.
Contact 3+socket 44
Contact 3+socket 35
Contact 2+socket 35
Specification: ∞ω

If no wiring fault is detected and voltage was present between contacts 1+3:
- Renew distributor with Hall sender
=>Page 76 , Item 15 .

If no wiring fault is detected and no voltage was present between contacts 1+3:
- Renew Simos control unit (J361)
=>Page 25 , item 9 .

1.9 - Checking knock sensor

Special tools, testers and auxiliary items

◆ Test box V.A.G 1598/18
◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715

1.8 - Checking Hall sender 83

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
◆ Adapter set V.A.G 1594
◆ Current flow diagram

Test sequence
- -> Separate blue 3 pin connector -2- to knock sensor 1 (G61) -1-.
- Connect multimeter with aux. cables from V.A.G 1594 to measure resistance at contacts 1+2, 1+3 and 2+3
on connector to knock sensor.
Specification ∞ω

If the specification is attained:

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- -> Connect test box V.A.G 1598/18 to control unit wiring loom. s
ce
e
nl

pt
du

an
itte

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erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nf
ercia

- -> Check wiring between test box and 3 pin connector for open circuit according to current flow diagram.
orm

Contact 1+socket 36
m

atio
m

Contact 2+socket 34
o

n in
c

Contact 3+socket 09
or

thi
e

Wire resistance: Max. 1.5 ω

t

sd
iva

- Additionally check wires for short to one another.

o
r
rp

cu

Contact 3+socket 34
o

m
f

en
ng

Contact 3+socket 36
t.
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op
Contact 2+socket 36 C py
t. rig
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cted agen
Prote AG.

84 28 - Ignition system
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
Specification: ∞ω

If no wiring fault is detected:

- Loosen knock sensor and tighten again to 20 Nm.

- Carry out test drive.

During the road test the following operating conditions must be fulfilled:
- The coolant temperature must exceed 80 °C .
- When the temperature is reached, the operating conditions
Idling
Part throttle
Full throttle
Overrun
must be attained several times.
- At full throttle the speed must exceed 3500 rpm.

- Again interrogate the control unit fault memory.

If the fault is still present:

- Replace knock sensor (G61) =>Page 74 , item 7 .

1.10 - Checking ignition transformer and output stage

Special tools, testers and auxiliary items

◆ Test box V.A.G 1598/18

◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
◆ Adapter set V.A.G 1594
◆ Diode test lamp V.A.G 1527
◆ Current flow diagram
AG. Volkswagen AG d
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Check conditions Volksw
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• Hall sender OK. rise nte
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Checking ignition transformer
ce
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un

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an
d
itte

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rm

ab
pe

ility
ot

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

nform
ercia

- Pull connector and H.T. cable off ignition transformer (N152).

- -> Check primary resistance between terminals 1 and 15.
m

a
com

Specification: 0.5...1.5 ω
ion in

- Check secondary resistance between terminals 4 and 15.

r
te o

thi

Specification: 2.5...4 kω
s
iva

do
r
rp

cum

If the specifications are not attained:

fo

en
ng

t.
yi Co
op
- Replace ignition transformer => Page 74 , item 4 . C py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

1.9 - Checking knock sensor 85

 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995
Checking voltage supply agen
AG. Volkswagen AG d
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- Pull 3 pin connector offiseignition
d b transformer. ara
nte
or eo
h
aut ra
ss c

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e
nl

pt
du

an
itte

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erm

ab
ility
ot p

wit
, is n

h re
hole

spec
es, in part or in w

t to the co
rrectness of i
l purpos

- -> Connect multimeter to measure voltage using aux. cables from V.A.G 1594 to the contacts 1+3 of the
disconnected connector.
- Switch ignition on.

nf
ercia

Specification: at least 11 V

orm
m

atio
m

If no voltage is present:
o

n in
or c

thi
te

- Switch off ignition.

sd
iva

o
r

- Check wire between 3 pin connector contact 1 and earth for open circuit according to current flow diagram.
rp

cu
o

Wire resistance: Max. 1.5 ω m

f

en
ng

t.
yi
- Check wire between 3 pin connector contact 3 and relay plate for open circuit according to current flow
Co
op py
diagram.
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ht ht
rig
Wire resistance: Max. 1.5 ω py by
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by lksw
cted agen
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Checking activation
AG.

- Pull connector off injectors.

- -> Connect diode test lamp V.A.G 1527 using aux. cables from V.A.G 1594 and adapters V.A.G 1594/15 to
contacts 2+3 of the connector.
- Operate starter and check ignition signal from Motronic control unit.
LED must flicker

The LED does not flicker:

86 28 - Ignition system
 Caddy 1996 , Polo Classic 1996 ➤
Simos injection and ignition system - Edition 11.1995

- -> Connect test box V.A.G 1598/18 to control unit wiring loom.
- Check wire between test box socket 7 and 3 pin connector contact 2 for open circuit according to current
flow diagram.
Wire resistance: Max. 1.5 ω
- Additionally check wires for short to one another.
Specification: ∞ω

If no wiring fault is detected and voltage was present between contacts 1+3:

- Renew Simos control unit (J361)

=>Page 25 , item 9 .

If the voltage supply and activation is OK.:

- Connect 3 pin connector and H.T. cable to ignition transformer.

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d
itte

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erm

ab

- -> Connect diode test lamp using aux. cables and clamps to the contacts 1 and 15 on ignition transformer.
ility
ot p

wit
is n

h re

Warning!
ole,

During the following test do not touch the terminals of the ignition transformer or test cables.
spec
urposes, in part or in wh

t to the co

- Operate starter.
The LED must flicker
rrectness o
cial p

f inform
mer

atio
om

n
c

i
or

n thi
te

sd
iva

o
pr

cum
r
fo

en
ng

t.
yi Co
Cop py
t. rig
gh ht
pyri by
Vo
co lksw
by
cted agen
Prote AG.

1.10 - Checking ignition transformer and output stage 87