254

Service.

AUDI A4´01 - Technical Features

Design and Function

Self-study programme 254

For internal use only.

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 Advance by technology

The new Audi A4,

a vehicle which combines driving pleasure and good sense

with the highest level of quality and sports styling.

Control unit for vehicle electrical system...48

New engine programme ...18

Electronic stability programme with

brake assistance ...32

Steering column switch module ...44

Crash sensors for front airbag ...14

Multi-communication bar ...72

Trapezium link
rear axle...27

Aero-floor ...7

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 Contents

Page
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Occupant protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Engine and gearbox

2.0 l R4 and 3.0 l V6 engines (see SSP 255) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Innovations - 2.5 l V6 TDI engine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Innovations - automatic gearbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Running gear
Axles ............................................................ 26
Mechanical unit mountings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Brake system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Brake assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Electrical system
Vehicle electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
CAN BUS system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Dash panel insert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Steering column switch module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..44
Function circuit diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Control unit for vehicle electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Function circuit diagram for "lowline" version . . . . . . . . . . . . . . . . . . . . . 50
Function circuit diagram for "highline" version . . . . . . . . . . . . . . . . . . . . 52
Convenience system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Anti-theft alarm system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Radio - chorus II, concert II and symphony II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Navigation IV and Navigation Plus-D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Multi-communication bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Electric logbook "Audi Logbook" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Heater/AC
Design and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
7-piston compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Glove compartment cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Solar roof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Fresh air blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Actuators/sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Functional diagram for fully automatic air conditioner . . . . . . . . . . . . . . 84
Additional heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Important:
New
Note
The self-study programme will provide you with information on
design and functions.

It is not intended as a workshop manual.

For maintenance and repair operations it is essential that you

refer to the current technical literature.
3

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 Introduction

The architecture of motion

Performance and smooth running

The engine programme of the new Audi A4

includes two petrol engines of a completely
new design, with aluminium housings.
The 2.0 litre 4-cylinder in-line engine with
96 kW (130 PS) and the 3.0 litre V6 with
162 kW (220 PS) fulfil the EU 4 emissions
standard.
A high degree of running smoothness is
achieved via balancer shafts.

Infinitely variable perfection

For the first time in this vehicle class, Audi

offers the infinitely variable "multitronic"
automatic gearbox for all front-wheel drive
versions.

The new light alloy running gear

With the four-link front axle, each wheel is

controlled by four aluminium transverse links.
The pivot bearings are also made from the
same light alloy.

The trapezium link rear axle for the quattro

drive system is also used in the front-wheel
drive models of the Audi A4.

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 Finely-tuned aerodynamics

Despite the greater frontal area and the cool-

ing air current for the air conditioner (stand-
ard), it was possible to improve the CD value
by 5 %, in comparison to its predecessor,
to 0.28.

A special feature is the so-called aero-floor,

which provides for optimal airflow on the
underside of the vehicle.
High safety standards

With a thoroughly optimised body design and

comprehensive safety equipment, the new
Audi A4 is able to comply with all current valid
safety standards, throughout the world.
Crash sensors for the front airbags integrated
directly into the bumper bar, improve occu-
pant protection.

Communication centre on wheels

With regard to infotainment, the new

Audi A4 leaves nothing to be desired.
4 different audio systems, 2 differently config-
ured Navigation systems and a car phone
with voice operation are on offer.

SSP254_048

Electronic stability programme (ESP)

including brake assistant

For the latest ESP generation, the hydraulic

brake assistant is an integral part of the
standard equipment.
It is intended to assist the driver by automati-
cally increasing the brake pressure during
emergency braking.

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 Introduction

Vehicle dimensions of Audi A4´01

1628
901

106/110

1528 1526

1766 1937
977

951

471
799 445 L

1050 870

976
303
257

921 2650 976

4527
1000
1400

1357

1088

SSP254_051

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 The aero-floor
not only contributes to improved aero- The aero-floor was designed so as to guaran-
dynamics. tee ground clearance and resistance to stone
It was also possible to reduce the noise level impact and to prevent accumulation of dirt,
by approx. 3 dB (A). stones and snow.

Front-wheel drive

Four-wheel drive quattro and V6 engine

SSP254_053

Part of the additional costs generated by the

aero-floor could be compensated by dispens-
ing with certain panelling components as The engine compartment noise insu-
well as by dispensing with PVC protection of lation does not form part of the aero-
the underside of the vehicle. The latter is of floor.
advantage during recycling.

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 Body

Front impact design features

The new Audi A4 is designed for optimal con- – the straightened longitudinal member with
formance with current crash requirements crash-optimised octagonal cross-piece
and safety standards. – the rigid and significantly wider bumper
This could only be achieved by increasing the cross-piece
body weight. – the integration of the member structures
into the passenger cell
In order to reduce this additional weight to a – strength, rigidity and weight-optimised
minimum, the proportion of light-weight suspension strut cross-piece
materials has been increased in comparison
to its predecessor.
The proportion of high-strength sheet metal
parts as well as the use of a total of 10 large
component "tailored blanks", contribute sig-
nificantly to weight reduction.
Body rigidity has been increased by 45 % by
increasing the number of connection points
by 25 %.

SSP254_054

Depending upon vehicle weight, performance and fuel consumption are the characteristics
which our customers can experience at first hand.

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 Side impact design features

In the floor area, the cell consists of three

large tailored blanks, which ensure a stable
connection between the front and rear of the
vehicle.

Weight-saving optimisation of deformation

characteristics in the event of a side impact
was achieved by the use of an aluminium
extruded profile in the sill.

“tailored blanks” are made-to-measure

sheet metal parts with varying material
thickness.
SSP254_055

SSP254_056

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 Body

Doors

The doors of the Audi A4 demonstrate a sig-

nificantly increased rigidity due to the one-
piece door shell construction.

For the first time, a so-called spray-on noise

insulation is used, which is sprayed on as
required and allows weight reduction for the
same effectiveness.

Noise insulation

SSP254_067

The newly developed sub-frame is bolted to

the door shell via fitted bolts.

SSP254_066

Roof
In addition, the doors have been fitted with a
Roof trim strip
second weatherseal. One weatherseal is fitted
to the door and the other is fitted to the body.
Door window
The new door concept permits a reduction in seal
the overall noise level of a further 3 dB (A) and
thus contributes to improving the aero-acous-
tics.

Door window
Door trim

Door seal Door frame seal

Door frame SSP254_075

10
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 Emergency door locking

In the event of failure of the central locking,

e.g. due to power supply faults, each door can
be individually locked without using the lock
cylinder.

Firstly, with the door open, the cap must be

removed. Emergency locking is effected by
inserting the ignition key.

After the door has been closed, it is not possi-

ble to open it from the outside.
The door can be opened from the inside by
actuating the door release handle twice. SSP254_069

Luggage compartment lid

The luggage compartment lid should always

be operated via the radio remote control.

The lock cylinder for the luggage compart-

ment lid is integrated into the handle.

Continuous locking of luggage compartment SSP254_070

If the lock cylinder is in the horizontal posi-

tion with the key removed, the luggage com-
partment lid is no longer included in the
central locking system. Opening is then only
possible via the centre unlocking button of
the radio remote control.

When the lock cylinder is in the vertical posi-

tion, the lid is an integral part of the central
locking system.

SSP254_071

Manual unlocking and opening

is effected by turning the key to the left.

In this position, it is not possible to remove
the key, which must subsequently be returned
to the vertical position.
Thus, it is ensured that the luggage compart-
ment lid is an integral part of the central lock-
ing system.

SSP254_072

11

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 Occupant protection

Overview of system

G 283 G 284

J162 K145
J220 AIRBAG
OFF

J285/K75

J533
AIRBAG E224
T16
AUS EIN

N95
N131

J393 J234 J526

N199 N200

G179 G180
N153 N154

N201 N202

N277 N278

G 256 G 257

SSP254_029

12

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 To complement the comprehensive body The system comprises driver/passenger air-
modifications, occupant protection has been bags, front side airbags, optional rear side
improved through the further development of airbags, SIDEGUARDS®, three point front seat
the familiar 8.4 airbag system. belts with ball tensioners and belt force limit-
ers, three point rear outer seat belts, centre
lap belt (for fixed rear seat bench), Isofix pre-
paration in rear of vehicle, and a total of 6
non-central accelerometers:

– 2 front impact crash sensors

– 2 driver/passenger side airbag crash sen-
sors, (in the B-pillar for side impact)
The new generation bears the designa- – 2 driver/passenger rear side airbag crash
tion 8.4 E, where the E stands for sensors, (on the C-pillar for side impact)
"extended".

The position of the sensors is selected so that The external sensors deliver digitised acceler-
they are installed as near as possible to the ation data to the airbag control unit, which is
outer structure of the vehicle. then evaluated in the control unit and which
This enables quicker deceleration detection in triggers the relevant restraint system compo-
the event of an impact. nents.

Key

E224 Key switch for switching off K75 Airbag warning lamp
passenger’s side airbag K145 "Airbag off" warning lamp,
G179 Side airbag crash sensor, driver’s passenger's side
side (B-pillar) N95 Airbag igniter, driver's side
G180 Side airbag crash sensor, passenger’s N131 Airbag igniter 1, passenger's side
side (B-pillar) N153 Igniter for belt tensioner, driver's side
G256 Crash sensor for rear side airbag, N154 Igniter for belt tensioner,
driver’s side passenger's side
G257 Crash sensor for rear side airbag, N199 Igniter for side airbag, driver’s side
passenger's side N200 Igniter for side airbag, passenger's
G283 Front airbag crash sensor, driver’s side
side
G284 Front airbag crash sensor, N201 Igniter for rear side airbag,
passenger’s side driver’s side
J162 Heater control unit N202 Igniter for rear side airbag,
J220 Control unit for motronic passenger's side
J234 Airbag control unit N277 Igniter for airbag in B-pillar
J285 Control unit with display unit in (SIDEGUARD®), driver's side
dash panel insert N278 Igniter for airbag in B-pillar
J393 Central control unit for convenience (SIDEGUARD®), passenger's side
system T16 Connector, 16-pin, diagnosis
J526 Control unit for telephone / connection
telematics
J533 Diagnosis interface for data bus
(Gateway)
13

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 Occupant protection

Crash sensors for front airbag G283, 284

Both sensors for front impact detection func- If a certain signal threshold is exceeded in the
tion in conjunction with the crash sensor and front airbag crash sensor, a threshold reduc-
the safe sensor which are integrated into the tion is activated in the airbag control unit,
airbag control unit J234. which results in a shorter triggering time.

Upper body
SSP254_058
Head
Triggering of belt tensioners

Triggering of front airbags

the steering column

Damping function
Front airbags inflated

Vehicle rebound
Belt force limiter
Deceleration load

response in
response
Impact

Time [ms] SSP254_063

14 SSP254_064

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 Crash sensors for side airbags
G179, 180, 256, 257

In order to trigger the components of the

restraint system, two simultaneous impact
detection signals are required for the plausi-
bility check:

– from both opposing crash sensors

(B-pillar left with right and/or
(C-pillar left with right) and
– from the control unit internal crash sen-
sors.

The crash sensors are designed in such a way

that incorrect installation is excluded.

SSP254_059

Airbag control unit J234

The warning lamp for airbag K75 is activated Re-encoding of the airbag control unit is no
continuously following a detected impact. longer possible after the first crash data mes-
"CRASH DATA STORED" and the triggered sage is stored.
components are displayed with fault code
during fault memory readout. Triggering is performed in two thresholds
depending upon the deceleration value:

– Threshold 1 = belt tensioners only

– Threshold 2 = belt tensioners and airbag(s)

Sensors and components to be replaced

following an accident, are listed in the
current workshop manual.

15

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 16
Occupant protection

Deactivation of passenger airbag

Deactivation of the passenger airbag is only

possible via the key switch. In the Audi A4, the
passenger's side airbag is also deactivated.
Deactivation via the diagnostic tester is not
possible.

If a customer requires the deactivation func-

tion where a key switch is not fitted, this can
only be achieved by retrofitting the key switch
and airbag OFF lamp and by re-encoding of
the airbag control unit.

Front belt attachment

Belt lock and strap fastenings are perma-

nently connected to the seat frame. Thus, in
conjunction with the seat belt height adjuster,
an optimal belt fitting can be achieved for
each seat position.

Front head restraints

In order to offer a high degree of occupant

protection in conjunction with the seat belt
and airbag, the front head restraints have
been supplemented by an integral locking
mechanism.

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a
SSP254_101

SSP254_011

SSP254_102
 Crash signal processing

There are two separate crash signal outputs:

One crash signal is output via the conven-

tional wiring and triggers the following func-
tions:

– Transmitting an emergency call via the

control unit for telephone/telematics J526
(optional)
– unlocking the vehicle,
– Switch on interior light
(switch must be set to door contact),
– switching on hazard warning lights via the
central convenience electronics J393.
The auxiliary heater J162 (optional) is
switched off by the central convenience
electronics J393 via a CAN convenience
message.

The second crash signal output functions via

the convenience CAN bus, which switches off
the engine fuel supply via the engine control
unit J220.

17

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 Engine and gearbox

Engine

The 4-cylinder, 2.0 l engine

provides high propulsive force due to the

maximum torque of 195 Nm at 3300 rpm.

Power output [kW]

Torque [Nm]

SSP254_038 Engine speed in rpm SSP254_060

The 3,0 l V6 engine

with five-valve cylinder head, produces162 kW

(220 PS) at 6300 rpm from 2976 cm3.
The maximum torque of 300 Nm is developed
at 3200 rpm.

Power output [kW]

Torque [Nm]

Engine speed in rpm SSP254_061

SSP254_030
Detailed information on these engines
can be found in SSP 255.
18

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 Innovations 2.5 l V6 TDI engine

Power output [kW]

Torque [Nm]
SSP255_045 SSP255_039
Engine speed in rpm

Technical data

Capacity: 2496 cm3 Injection system: Bosch VE VP 44 S3.5

Bore: 78.3 mm Turbocharger: VNT 20

Stroke: 86.4 mm Exhaust emissions class: EU 3

Compression: 18.5 : 1 Consumption: urban 11.0 l/100 km

(6-gear, quattro) country 6.1 l/100 km
Power output: 132 kW (180 PS) average 7.8 l/100 km

Torque: 370 Nm at 1500 rpm

The main features of the basic engine are the The injection system was modified in order to
same as those of the familiar V6 TDI engine reduce exhaust gas and particle emissions.
with 132 kW (180 PS).

Power output and torque curve values could

be maintained under conditions which were
well within EU 3 limit values.
Limit value [%]

EU 3 limit values 100 %

Particle = 0.05 g/km
CO = 0.64 g/km
HC+NOx = 0.56 g/km
NOx = 0.50 g/km

NOx HC+NOx CO Particle

SSP255_038
19

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 Engine and gearbox

Injection pump VP 44 S3.5

Forced flush
return

Distributor bushing

Distributor shaft

Solenoid valve

Supply piston

Thermal shoulder

Forced flush feed SSP255_040

The high pressure section of the injection In order to initiate pre-injection for cold and
pump has been redesigned with regard to warm engines, the solenoid valve dynamics
pressure levels and quicker solenoid valve have been significantly increased.
actuation. The associated increased heat generation in
the solenoid valve, is compensated by
The injection pressure at part throttle has improved fuel flow and optimal filling of the
been increased by the following measures: high pressure section is achieved.

– increased cam stroke from 3.5 to 4.0 mm Noise levels have been significantly improved
– more stable support structure for high by the pre-injection for cold and warm opera-
pressure section on pump body tion and the use of dual-spring nozzle hold-
– conversion from 3 pistons with a diameter ers.
of 6.0 mm, to 2 pistons with a diameter of
7.0 mm.

By reducing the number of high-pressure pis-

tons from 3 to 2, it was possible to reduce
high-pressure leakage via the sealing sur-
faces.
Previously, pre-injection via the solenoid
valve was only realised during the engine
warm-up phase.

20

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 Injector

For the first time, an ICU injector (Inverse Cav- Due to the improved spray formation through
ity Undercut) is used, which has a dual needle the use of the ICU injector, it was possible to
guide. reduce the exhaust emissions and the particle
values by up to 20 %.
The advantage of this ICU geometry is a sig-
nificantly improved spray formation, espe-
cially in the part throttle range for small
injection quantities and short needle lift.

ICU seat geometry

SSP255_041

Dual needle guide

SSP255_042
ICU seat geometry Standard seat geometry

21

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 Engine and gearbox

Charge air cooler

Through duct
Cooling duct section

SSP255_043

The existing series connection of the two The charge air cooler design comprises two
charge air coolers for the 110 kW engine is sections, in which part of the charge air is fed
inadequate for the 132 kW engine with its via a through duct, connected to a space-sav-
high air throughput. ing pipe, to the section of the other charge air
cooler which is fitted with cooling fins.
A new charge air cooler design was devel- The rest of the charge air is fed directly
oped, in order to ensure optimal charge air through the cooling fins, via a separate pipe,
flow. to the second charge air cooler and into the
through duct.

22

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 Innovations - automatic
gearbox
5-speed 01V automatic gearbox

The Audi A4 quattro MJ01 with 5-speed auto-

matic gearbox features a new shift lever gate,
together with a new shifting concept.

The existing selector lever positions, 4,3,2 are

discontinued and are replaced by the "S"
position.

Gearshift positions 4,3,2 have been discontin-

ued as they are hardly ever used in practice. P

The DSP (dynamic shift programme) and "tip- R +

tronic" function have basically rendered them N

D
superfluous. S

With the selector lever is in the "S" position, a

sports shift programme provides the relevant
driving dynamics. In position "S", the DSP
also provides for adaptation of the driving set
values to the driving conditions.

The introduction of the "S" programme ena-

bles a significant extension of the useful shift
range between economy and sports.

The "S" programme comprises the following

special features: SSP254_117

– If, during driving with constant accelerator Example: Dynamics code 40

pedal position, the selector lever is set to Shift map 1
the "S" position, the system always shifts
down, within defined limits.
– In order to achieve a direct driving reaction
in response to accelerator pedal actuation,
Throttle valve angle [%]

the converter clutch is closed during driv-

ing operation, where possible.
– If, in conjunction with the overall gearbox
ratio, 5th gear is designed as overdrive
gear (overdrive, 4+E), only 1st -4th gears
are shifted.

We recommend the multi-function steering

wheel (available as optional extra) with steer-
ing wheel "tiptronic" ("thumb shifting").

Gearbox output speed [rpm]

D - normal driving programme SSP254_103

S - sports driving programme

23

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 Engine and gearbox

"multitronic" and 5-speed automatic gearbox

SSP254_088

An innovation for all automatic gearboxes is Special feature:

the "Tip in D " function. This means that the
steering wheel "tiptronic" function is now The countdown from approx. 10 seconds to
also available in selector lever position "D". return to normal automatic operation is inter-
rupted, in the event that cornering is detected
The transition to the "tiptronic" function is or the vehicle is in overrun operation.
effected by actuating one of the two tip
switches on the multi-function steering wheel When normal driving conditions are detected
(selector lever in position "D"). The system again, the countdown recommences from
then switches to the "tiptronic" function for approx. 10 seconds.
approx. 10 seconds. All gears can be shifted
within the range of permissible engine
speeds.
The system returns to normal automatic oper-
ation approx. 10 seconds after the last tip
request.

24

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 Notes

25

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 Running gear

Axles
Four-link front axle

The thorough further development of the

light-weight construction resulted in a weight
reduction of approx. 8.5 kg at the front axle.
In addition to all transverse links, the pivot
bearing is now also made of aluminium.
The wheel bearing is attached to the pivot
bearing via four bolts. The wheel hub can be
pressed in and out.

Aluminium mounting bracket SSP254_087

Aluminium
spring plate
Shock absorber valves

Aluminium pivot bearing

SSP254_086

The suspension strut mounting is of the bulky

rubber bearing construction.
It consists of two functional components:

– The inner part forms the connection to the

piston rod.
– The larger outer part provides for acoustic
insulation of the shock absorber.

SSP254_085

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 Trapezium link rear axle

The rear axle design with largely identical Apart from the axle mounting, the two axle
components is used in both the front-wheel versions differ only in the wheel carrier and
drive as well as in the quattro versions. the wheel bearings.

Camber
adjustment

SSP254_089
Toe adjustment

The front-wheel drive version is fitted with a

wheel bearing unit with integral wheel hub,
which is mounted on a stub axle forged
together with the wheel carrier.

SSP254_083

Camber
adjustment

SSP254_091
Toe adjustment

The wheel bearings of the quattro version

consist of pressed-in, double-row angular ball
bearings with conventional wheel hubs.

SSP254_082

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 Running gear

Mechanical unit mountings

Engine mounting 1

Cross member

Gearbox
mounting 3
Torque
member

SSP254_107
Engine
mounting 2

A newly designed three-point mechanical unit The additional cross member enables support
mounting is used in the new Audi A4. over a longer lever arm, which positively influ-
ences vibration and load cycle characteristics.
The hydraulically damped engine mountings
(electrically-controlled version for diesel The aluminium cross member is bolted to the
engines) are fastened directly to the longitu- body as well as to the rear subframe mount-
dinal members via die-cast aluminium brack- ings and, in addition to its supporting func-
ets. tion for the gearbox mounting, serves as a
body-stiffening tunnel bridge.
The gearbox mounting is effected by means
of a conventional rubber bearing on a body-
mounted aluminium carrier, which is pro-
duced according to the hollow sand casting
technique.

The three-point mechanical unit mount-

ing is used for all engine/gearbox
combinations except those including
the 01V 5-speed automatic gearbox.

28

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 Brake system
The new Bosch ESP 5.7 is introduced in the
Audi A4. The ESP 5.7 is distinguished by the
following special features:

– The hydraulic unit and control unit form a

single unit.

– The charging pump (actuation of ESP

hydraulic pump V156) is discontinued.

– A brake assistant is included.

Hydraulic modulator

Due to the increased brake fluid viscosity at

extremely low ambient temperatures, the
required delivery rate for the return pump for
ABS V39 could not be achieved without a
charging pump (resulting from the increased
suction resistance in the system).

The purpose of the development of the

ESP 5.7 was to improve the suction of the ABS
return pump so that the charging pump was
no longer necessary.

The charging pump could be discontinued

through the use of a two-stage ABS return
pump, enlarging the cross-section of the SSP254_094
brake lines and the use of a larger-dimen-
sioned central valve in the brake master cylin-
der.

29

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 Running gear

Single-stage ABS return pump

Suction volumes

UT OT UT OT UT

Suction volumes

UT OT UT OT UT

SSP254_095

The graphic shows a comparison of the

suction volumes of both pump versions.

In the single-stage ABS return pump, the The suction pressure is correspondingly high
entire suction volume must be drawn in and and increases with increasing viscosity.
flow through the suction line during one Cavitation and the associated drop in
piston stroke (piston stroke from TDC to BDC). performance on the pressure side, are the
results.

30

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 Two-stage ABS return pump

Working chamber 2

Suction volumes

Working chamber 1
UT OT UT OT

UT OT UT OT

SSP254_096

The piston of the two-stage ABS return pump As the entire suction volume is supplied
is stepped and has a double-acting function almost continuously, the maximum suction
within two working chambers. flow rate is significantly lower, which dimin-
ishes the suction pressure and prevents
Suction is effected in two stages; brake fluid cavitation.
being drawn through the suction line during Thus, a quick pressure build-up is ensured,
each piston stroke. even at extremely low temperatures.

Function:

If the piston moves from BDC to TDC, the In working chamber 1, brake fluid is now
brake fluid in working chamber 1 is com- drawn via the open inlet valve, out of the suc-
pressed whereas working chamber 2 is simul- tion line and out of the connection line to
taneously under suction. working chamber 2.

If the piston then moves from The suction flow rate in the suction line is
TDC to BDC, the brake fluid which has been diminished by that amount which flows back
drawn into working chamber 2 is forced back out of the connection line from working
into the suction line against the inlet valve. chamber 2
(drawn in during previous working operation).

31

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 Running gear

Brake assistant
Investigations in accident research have During emergency braking, the brake assist-
shown, that the majority of drivers fail to ade- ant aids the driver by increasing the brake
quately actuate the brakes in an emergency pressure automatically, to a level exceeding
situation. the locking limit.
This results in insufficient brake pressure The ABS (Anti-lockbrakingsystem) is thus
being generated to achieve maximum vehicle quickly brought into the operating range,
deceleration. which enables a maximum vehicle decelera-
This lengthens the braking distance. tion to be achieved.

Brake servo pressure sensor G294 is used for

detection of emergency braking.

Pressure sensor G294

SSP254_093
Pressure [p]

For this purpose, the pressure increase gradi-

ent (pressure build-up with respect to time) is
evaluated and, if necessary, the brake assist-
ant is activated.

Time [t]
SSP254_092
Emergency braking

Normal braking distance

32

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 The function of the brake assistant is
sub-divided into 2 phases:

• Phase 1 • Phase 2

If the pressure increase gradient exceeds a If the pressure determined by the driver falls
specified value (emergency braking), the ABS below a certain value after triggering of the
return pump and the relevant solenoid valve brake assistant, the system pressure is
are activated by the ESP control unit and the restored to the pedal pressure determined by
brake pressure is thus increased into the ABS the driver.
control range, in a similar manner to that of
the control system for an electronic differen-
tial lock.

Brake assistant activated Brake pedal unloaded Brake assistant

switches off

Phase 1 Phase 2

ABS control
Brake pressure [p]

range

Time [t] SSP254_084

Brake pressure determined by an

experienced driver

Regulated brake pressure The integral inlet and outlet valves in the
(brake assistant) hydraulic modulator are no longer sim-
ply switched on/off, but are regulated
Determined brake pressure via supplied voltage.
insufficient inexperienced driver This enables more precise control on
extremely slippery surfaces, e.g. ice.

33

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 Running gear

Brake fluid reservoir

The brake fluid reservoir is secured with an

additional screw.

The new maintenance opening in the brake

fluid reservoir enables the extraction of brake
fluid from both brake fluid chambers.

The new brake filler and bleeder unit

VAS 5234 must be used for this purpose.

SSP254_098

Fastening screw
Maintenance opening

Brake light switch

The fastening and adjustment of the brake

light switch are new.

The brake light switch is secured to the pedal

bracket via a bayonet fitting.

The position of the push rod is adjusted for

the basic setting.

For this purpose, the brake light switch must

be released by turning it anti-clockwise.
The push rod catch is released simultane-
ously via the locking lug.

The push rod is now free and can be adjusted

without risk of damage.

The push rod is pulled out to the stop for the

basic setting. SSP254_099
The brake light switch can now be inserted
into the pedal bracket and secured by turning
clockwise. At the same time, the push rod
catch is locked automatically by means of the
locking lug.

34

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 Notes

35

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 Electrical system

Vehicle electrical system Control unit for headlamp

Chip card
reader R99
range control J431
Control unit for
telematics J499

Control unit for

mobile phone control
electronics J412

Battery

Control unit with

display in dash panel
insert J285

Front airbag crash

sensor, passen-
ger’s side G284

Control unit for

coolant fan, Control unit
Stage 1+2 J293 for ESP J104

Front airbag crash sen-

sor, driver’s side G283
Steering column
Control unit switch module J527
for Motronic J220
Control unit for auto-
matic gearbox J217

36

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 Side airbag crash sensor,
passenger’s side G180 Door control units,
passenger side J387
rear right,
Side airbag crash sensor, rear
optional J389
driver’s side G256
passenger’s side G257

Control unit for trailer

recognition J345

Control unit for

parking aid J446

Control unit for

tyre pressure
monitor J502

Airbag control
unit J234

Central control unit for

convenience system J393

Side airbag crash sensor,

driver’s side G179
ESP sensor

SSP254_008

Door control unit,

driver’s side J386,
rear left, optional J388
Control unit for vehicle electri-
cal system J519

37

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 Electrical system
CAN BUS networking

J285

Gate-
way

Diagnosis system
J507
J386 J387

J220
R99

J217 J388 J389

J499

J526
J104 J393
J502
TRACK
SEEK FR FF

EJECT

TUNE SCAN

CD CDC 1 2 3 4 5 6 AS

1 AM 2 TP
EJECT Audi symphony DOLBY SYSTEM

1 FM 2
BASS MIDDLE TREBLE BALANCE FADER RDS

PLAY SDE
TAPE RANDOM

J234 R
E87
J162

NOX sensor
(USA only)
J345 J446 J401

J527

J402

J519
G85 J136
J527
R94
+

-
R
T

J453
The ignition switch signals and the
control buttons for multifunction
and "tiptronic" steering wheel are
registered via the steering column
38 electronics.

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 CAN data bus

The Audi A4 is equipped with a widely

extended CAN data bus system.
For communication between the
installed control units and the diagnos-
Due to the ever increasing number of control
tic tester, two diagnosis wires (K and L)
units installed in the vehicle and the associ-
are available.
ated requirement for data exchange, the
importance of the CAN data bus system
increases significantly.

G85 Steering angle sender J402 Control unit for operating electronics,
E87 Operating and display unit for navigation, TV tuner
air conditioner J446 Control unit for parking aid
J104 Control unit for ESP J453 Control unit for multi-function
J136 Control unit for seat adjustment with steering wheel
memory, optional J499 Control unit for telematics
J162 Auxiliary heater, optional J502 Control unit for tyre pressure monitor
J217 Control unit for automatic gearbox J507 Control unit for speech entry
J220 Control unit for motronic J519 Control unit for vehicle electrical
J234 Airbag control unit system
J285 Control unit with display unit in J526 Control unit for telephone -
dash panel insert permanent installation
J345 Control unit for trailer recognition J527 Control unit for steering column
J386 Door control unit, driver’s side electronics
J387 Door control unit, passenger side R Radio
J388 Rear left door control unit, optional R94 Interface for navigation
J389 Rear right door control unit, optional R99 Chip card reader
J393 Central control unit for convenience
Drive BUS 500 kBaud
system
Convenience BUS 100 kBaud
J401 Navigation system control unit Display BUS 100 kBaud
Diagnosis connection
K wire
Diagnosis connection
L wire (2nd K wire)

The newly developed adapter VAS 6017 ena-

bles communication with all control units.

SSP254_112
39
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 Electrical system

Dash panel insert

Cruise control system ON

SSP254_012
Auto-check system

Setting buttons for digital clock, Call-up button for Reset button for trip
date and instrument illumination service interval recorder
indicator

There are two dash panel insert versions: The dash panel insert of the new Audi A4 is
equipped with
– "lowline"
– "highline" – the gateway for linking the three data bus
systems: drive, convenience, information
The "highline" version is equipped with a – and the immobiliser III.
high-quality colour display for the driver infor-
mation system and is installed in vehicles
with navigation systems as well as telematics.

40

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 User prompt in the centre display via the con-
trol switch in the centre console, is only avail-
able in vehicles with

– navigation system ("highline" version only)

and/or
– telematics and/or
– auxiliary heater and/or
– tyre pressure monitoring.

The optional driver information system

includes the following functions:

– radio clock
– auto-check system SSP254_104
– on-board computer.

The km range is indicated in the basic ver-

sion.

In order to ensure good signal reception for

the radio clock, the receiver is installed in the
rear bumper bar.

V
+5
h
Eart ig n a
l
d io s
Ra

SSP254_108

41

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 Electrical system

A new feature of the Auto-Check system

is the position-dependent bulb monitor display.

The fault message is transmitted from the vehi-

cle electrical system control unit J519, via the
convenience data bus, to the dash panel insert
J285 and appears on the centre display.

SSP254_118

Control unit with

display unit in dash
panel processor J285

Convenience data
bus

Control unit for vehicle

electrical system J519

SSP254_125

The Audi A4 quattro is equipped with two fuel

gauge senders G and G169.

Sender G registers the lower, and sender

G169 the upper partial volume in the fuel
tank.

The signals from senders G and G169 are

evaluated separately. The calculated litre
values are then added and displayed.
SSP254_123
Fuel gauge Fuel gauge
sender G sender 2, G169

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 Diagnostics

Control unit with

display unit in
dash panel insert J285

Convenience data
bus

Control unit for steering

column electronics J527 Terminal 15

Ignition lock D
SSP254_138

The dash panel insert checks the plausibility

– of both fuel gauge senders in quattro

vehicles
– as well as the terminal 15 input signal.

Due to the gateway function of the dash panel A further innovation is the display of the max-
insert, the communication with the individual imum and minimum engine oil levels in the
control units connected to the CAN data bus measured value block after the most recent
is checked during diagnosis. service operation.

Communication faults are entered into the The adaptation of the mileage/kilometre read-
fault memory. The current status can be read ing after replacement of the dash panel
in the measured value blocks. insert, is possible (several attempts) up to a
recorded distance of 5 km after installation.

43

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 Electrical system

Steering column switch

module
Due to the compact design of the newly
developed steering column switch module, it
was possible to minimise the amount of wir-
ing necessary and the space requirements.
Steering column
A self-diagnosis facility for the steering col- electronics J527
umn switch is now available with new switch
module.

The steering column switch module consists

of the following components:

– Turn signal switch

– Wiper switch with interval potentiometer
– Separate steering column switch cruise
control system operation
– Coil spring for diver's airbag
– Steering angle sensor for ESP
– Steering column electronics for signal con-
version and processing of drive and con-
venience CAN BUS J527

In addition, the steering column electronics

register the ignition switch signals. Turn signal
Furthermore, the control buttons for multi- switch E2
function and "tiptronic" steering wheel are
registered via the steering wheel electronics
module.

Steering column switch

Cruise control
Detection of the respective switch positions is system E45
effected via voltage coding, using various
resistance values in the relevant position. The
steering column electronics evaluates this
switch information and transmits it, via the
convenience CAN BUS, to the vehicle electri-
cal system control unit J519.

Cruise control system (CCS)

For ergonomic reasons, the control switch for

the cruise control system is located on the Ignition
left side of the steering column, below the steering lock
turn signal lever.

Warning lamp K31 in the dash panel insert

illuminates when the CCS is in control mode. SSP254_105

The modified operation of the CCS Steering

column switch function is described in the
Owner's Manual.
44

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 Ignition lock registration

The signals from the terminals:

– P parking light
– 86s ignition key contact
Wiper – 75 Load-reduction relay
switch E – 15 ignition ON
– 50 starter

are transmitted to the steering column elec-

tronics J527 via conventional wiring. The
switch positions of the ignition lock are pre-
pared by the electronics, supplied to the con-
venience CAN bus and then transmitted via
the gateway to the drive and infotainment
CAN bus systems.
Steering angle
sensor G85

Steering angle sender G85

The determination of steering angle is per-

formed via optical elements in the steering
Coil spring column electronics J527 and is supplied to
the drive CAN BUS.
The current steering angle position is thus
made available to the ESP control unit.

For further information on the optical

steering angle sensor, please refer to
SSP 204.

Self-diagnosis

Communication between the diagnostic

tester and the steering column electronics
J527 is effected by means of the convenience
R
T data bus via the central convenience electron-
ics J393, as no separate K wire is connected
to the steering column electronics.. (see
graphic 254 018 on Page 57)

Steering column electronics The steering column electronics module with

module J453 with operating operating unit for "tiptronic", multi-functions,
unit E221 horn etc., is incorporated in the self-diagnosis.
SSP254_014

Address word 16
The steering column switch module
After the addressing, the tester answers with
must always be coded.
the text "steering column electronics".

45

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 Electrical system

Functional diagram
Steering column switch
module
(maximum equipment)
Colour coding
Components
= Input signal
E Windscreen wiper switch
E2 Turn signal switch = Output signal
E45 CCS switch
E221 Operating unit in steering wheel = Positive power supply
G85 Steering angle sender
H Horn actuation = Earth
J234 Airbag control unit
J453 Control unit for multi-function = CAN-BUS
steering wheel
J527 Control unit for steering column
electronics
S Fuse
Z36 Heated steering wheel Auxiliary signals

1 CAN screen drive

2 Emergency vehicle distress radio

3 Emergency vehicle radio

4 Cruise control system on/off

5 CAN low convenience

6 CAN high convenience

7 CAN low drive

8 CAN high drive

9 Ignition lock terminal 75

10 Ignition lock S contact

11 Ignition lock terminal 15

12 Ignition lock terminal 50

13 Ignition lock terminal P

Y
{ Connection within the functional
diagram
Z

46

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 +

R/T

S13/
10A
H

J453 E221

Z36

1 2 3 4 5 6 7 8
G85

Z
Y
J234 X

J527

Z X
Y

9 10 11 12 13

E45 E2

31 31

in out

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 Electrical system

Control unit for vehicle

electrical system J519
The control unit for vehicle electrical system The power connections for the individual con-
J519 is the newly developed electronic central sumers are driven via semi-conductor ele-
electrics and comprises a comprehensive ments, e.g. transistors.
self-diagnosis, which can be selected directly A separate supply is not required, as this is
with address word 09. provided by the internal electronics in the
event of a fault.
The control unit for vehicle electrical system
receives the input signals from the conven-
ience CAN BUS via the steering column
switch module or the rotary light control.

J4
Control unit for
Dual tone-
speech entry J507
horn H2/H4

Pb 1J0
915
105
AC

Wiper system
Power supply Control unit for
vehicle electri-
cal system J519

Hazard warning lights switch E3

Rotary light control E1

Lighting system

Relay for
X contact J18
Steering col-
umn electron-
ics J527 Control unit for trailer
recognition J345

SSP254_068

Dash panel insert J285

48

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 There are three control unit versions:

– "lowline" for the standard version

– "lowline" for vehicles with headlight
washer system
– "highline" for vehicles with driver informa-
tion system

The following functions are available with the The "highline" version implements the driver
"lowline" version: information system function and also
performs the following control functions:
– Wash/wipe control and interval
– Hazard warning and turn signal control – Driving light and dipped beam left/right,
– Actuation of horn and load-reduction relay – Fog lights and rear lights,
– Parking light left/right – Reversing lights,
– Side light left/right – Brake lights
– Main beam left/right and headlight flasher
– Number plate light with separate outputs to each of the individ-
ual consumers.

Light control

In the highline version, light control is trans-

mitted from the steering column switch
module or directly from the rotary light
control, via the convenience data bus, to the
vehicle electrical system control unit.

Side lights

Dipped beam*

Control unit for Fog lights*

vehicle electrical
system J519 Rear fog lights*

Parking lights

Main beam

Headlight flasher

*Inthe "lowline" version, the components marked with

an asterisk are connected via conventional wiring and
fuses, directly to the lighting units.
49

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 Electrical system

Functional diagram
Control unit for vehicle
electrical system J519
"lowline" version

Components
V11 Pump for headlight washer
E1 Light switch conditioning system
E3 Hazard warning light switch V48 Servo motor for headlight range
F Brake light switch control, left
F4 Reversing light switch V49 Servo motor for headlight range
F216 Contact switch for switchable control, right
rear fog lights X Number plate lights
H2 Treble horn
H7 Bass horn
J4 Relay for dual tone horn
J59 Load-reduction relay for x contact Colour coding
J345 Control unit for trailer recognition
J446 Control unit for parking aid = Input signal
J519 Control unit for vehicle electrical
system = Output signal
L22 Bulb for fog light, left
L23 Bulb for fog light, right = Positive power supply
L46 Bulb for rear fog light, left
L47 Bulb for rear fog light, right = Earth
M1 Bulb for side light, left
M2 Bulb for rear light, right = CAN-BUS
M3 Bulb for side light, right
M4 Bulb for rear light, left Auxiliary signals
M5 Bulb for turn signal light, front left
M6 Bulb for turn signal light, rear left 1 CAN high convenience
M7 Bulb for turn signal light, front right
M8 Bulb for turn signal light, rear right 2 CAN low convenience
M9 Bulb for brake light, left
M10 Bulb for brake light, right 3 Terminal 75
M16 Bulb for reversing light, left
M17 Bulb for reversing light, right 4 not fitted with trailer coupling
M18 Bulb for side turn signal light, left
M19 Bulb for side turn signal light, right 5 only with trailer coupling
M25 Bulb for high-level brake light
M29 Bulb for dipped beam headlight, left 6 Automatic gearbox "multitronic"
M30 Bulb for main beam headlight, left
M31 Bulb for dipped beam headlight, right 7 Manual gearbox
M32 Bulb for main beam headlight, right
S Fuses A
U10 Socket for trailer operation
V
V5
Windscreen wiper motor
Windscreen washer pump
U

X
{ Connection within the
functional diagram
Y

Z
50

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 30

H2
S36 S37 S19 S14 S20 S40
30A 20A 15A 10A 15A 25A
H7

E1

J59 F M25 L47 M17 M10 M2 M8 M19 M7 M3 M32 M31 V49 L22 L23 J4
1
0 2

58s

U 5
X Z 4 Z

J519

30 X

S27 S77
A 5 S21
15 30A 30A 15 15A
6

Y U 5 7
J345

3 2 1
M M
M
A 5
X X F4 L46 M16 M9 M4 M6 M18 M5 M1 M30 M29 V48 V5 V11 V E3
J446

F216
U10
in out

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 Electrical system

Functional diagram
Control unit for vehicle
electrical system J519
"highline" version

Components
V11 Pump for headlight washer
E1 Light switch conditioning system
E3 Hazard warning light switch V48 Servo motor for headlight range
F Brake light switch control, left
F216 Contact switch for switchable V49 Servo motor for headlight range
rear fog lights control, right
H2 Treble horn X Number plate light
H7 Bass horn
J4 Relay for dual tone horn
J59 Load-reduction relay for x contact
J345 Control unit for trailer recognition
J446 Control unit for parking aid
J519 Control unit for vehicle electrical Colour coding
system
L22 Bulb for fog light, left = Input signal
L23 Bulb for fog light, right
L46 Bulb for rear fog light, left = Output signal
L47 Bulb for rear fog light, right
M1 Bulb for side light, left = Positive power supply
M2 Bulb for rear light, right
M3 Bulb for side light, right = Earth
M4 Bulb for rear light, left
M5 Bulb for turn signal light, front left = CAN-BUS
M6 Bulb for turn signal light, rear left
M7 Bulb for turn signal light, front right
M8 Bulb for turn signal light, rear right
M9 Bulb for brake light, left
M10 Bulb for brake light, right
Auxiliary signals
M16 Bulb for reversing light, left
M17 Bulb for reversing light, right
1 CAN high convenience
M18 Bulb for side turn signal light, left
M19 Bulb for side turn signal light, right
2 CAN low convenience
M25 Bulb for high-level brake light
M29 Bulb for dipped beam headlight, left
3 Terminal 75
M30 Bulb for main beam headlight, left
M31 Bulb for dipped beam headlight, right
4 Terminal 31
M32 Bulb for main beam headlight, right
S Fuses
U Connection within the functional
U10 Socket for trailer operation
diagram
V Windscreen wiper motor
V5 Windscreen washer pump

52

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 30

15

H2
S36 S37 S14 S7 S40
30A 20A 10A 10A 25A
H7

E1

J59 0
1
2
F M25 L47M17M10 M2 M2 M8 M19 M7 M3 M32 M31 V49 L22 L23 J4
A

15 58s

J519

30

S27 S77
15 30A 30A

U
J345

3 2 1
M M
M
4
X X L46 M16 M9M4 M4 M6 M18 M5 M1 M30 M29 V48 V5 V11 V E3
J446

F216
U10
in out

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 Electrical system

In the "highline" version of the vehicle electri-

Rear lights on:
cal system control unit, only the 21 watt
Brake actuated
filament of the two-phase bulb for the brake
and rear light is used.
Measuring equipment Recorder operation
DSO
With lights switched on and non-actuated 5 V/Div.= 10 ms/Div. Photo

brakes, the power rating is reduced to 5 watts Channel A

by a pulse-width modulated signal via the Channel B

vehicle electrical system control unit J519. Trigger mode

T Measuring

Thus a self-diagnosis/driver information mode

Cursor 1
system (FIS) is possible for the second rear 0

light. Cursor 2

A defective brake light would be indicated in

FIS. Position Time/Div. Multimeter

Skip Print Help

Brake not actuated SSP254_080

For non-plausible condition of the rotary

light control, the side lights and low beam
In vehicles with the "highline" version, national
are switched on automatically by the vehi-
lighting regulations can be adapted via
cle electrical system control unit in the
coding.
"highline" version.

Electrical fault finding

In certain lighting circuits, an open-circuit

voltage measurement using the Multimeter is
Reversing lamp on:
not possible, as the semi-conductor elements
are clocked until the circuit is again closed.
Measuring equipment Recorder operation
DSO
For defective bulbs which are operated via the 5 V/Div.= 2 s/Div. Photo

vehicle electrical system control unit J519, no Channel A

permanent fault storage is effected, but only

Channel B

for the period of the fault.

This means that the fault memory must not
be erased after changing a defective bulb. Measuring
mode

Cursor 1

1 0 Cursor 2

2
Position Time/Div. Multimeter

3 Vehicle Print Help

self-diagnosis

SSP254_052
1 - bulb illuminates
2 - bulb failure
3 - clock frequency of power output

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 Turn signal/hazard warning light control

The functions: The hazard warning flasher signal is control-

led separately by the vehicle electrical system
– Anti-theft alarm flasher control unit, via the hazard warning flasher
– Central locking system flasher when button.
opening/closing If, during hazard warning flashing, the turn
– Key-learn flasher for key adaption signal flasher is actuated, e.g. during towing,
– Crash flasher the hazard warning lights lose their priority
– Panic flasher (USA only) for this period.

are specified by the central convenience elec- The turn signal clicking is generated by an
tronics and transmitted via the convenience integral acoustic relay in the dash panel
data bus to the vehicle electrical system con- insert.
trol unit, which then executes the "com-
mands". For active hazard warning flasher with
ignition OFF, the flasher bulbs are actu-
ated for a shorter period in order to mini-
mise current consumption.

Turn signal light, right

Turn signal light, left SSP254_077

The signal for turn signal flashing or motor- Motorway flashing is detected by the vehicle
way flashing is output via the steering column electrical system control unit when the turn
switch module and executed by the vehicle signal lever is pressed and this triggers a tri-
electrical system control unit. ple turn signal flash.

Turn signal light, right

Turn signal light, left

SSP254_078

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 Electrical system

Wash/wipe system

The wash/wipe system is equipped with the The windscreen wash/wipe relays are inte-
speed-dependent 4-stage interval system. grated into the vehicle electrical system
control unit J519.
A new feature is the re-wipe function for the
windscreen washer system. The washer fluid reservoir is a two-part
Re-wiping occurs automatically 5 seconds design for easier removal and installation.
after the wash procedure is completed. An additional sensor is fitted for vehicles with
headlight washer system (HWS). In the
"highline" version, this is also used for the
Check system.
The purpose of the sensor, is to switch off the
HWS pump via the vehicle electrical system
control unit.
This prevents the pump running dry.

Reservoir in engine
compartment

Reservoir in front left

wheel housing

Connected

Windscreen washer fluid

Windscreen and level sender G33
rear screen washer
pump V58

Headlight washer sys-

tem pump V11 SSP254_024

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 Control unit for trailer recognition J345

A separate control unit is required for trailer

operation. This transmits the vehicle lighting
system convenience CAN messages from the
vehicle electrical system control unit to the
trailer lights. A parallel link from the trailer
socket to the vehicle wiring would result in
fault detection via the microprocessor in the
vehicle electrical system control unit.

The diagnostic function of the control unit for

trailer recognition is performed via the
vehicle electrical system control unit J519,
address word 09.

SSP254_016
Address word 09 - vehicle electrical system/
Central convenience In the case of faulty communication
electronics between the control unit for trailer recog-
nition and the vehicle electrical system
Communication takes place by means of the control unit, the rear lights are actuated
convenience data bus via the central conven- as a warning signal.
ience electronics, as no separate K-wire
leads to the vehicle electrical system control
unit. For this reason, intact central conven-
ience electronics are essential for perform-
ing self-diagnosis.

J387
J386
Door control units
Vehicle self-diagnosis 09 – Electronic central electrics
8E0907279B
int. load module RDW 0811
Code 101
Dealership No. 6803
02 - Interrogate fault memory
03 - Final control diagnosis
04 - Basic setting
05 - Erase fault memory
06 - End output
07 - Encoding control unit
08 - Read measured value block
09 - Read individual measured value
10 - Adaption J388 J389
11 - Log-in procedure

Measuring
Skip Print Help
equipment

VAS 5051 Control unit for vehicle

electrical system J519
CAN
BUS
K wire Control unit for trailer
recognition J345
Central convenience
electronics J393
Steering wheel
electronics
R
T

module J453
SSP254_018
Steering column
switch module J527
57
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 Electrical system

Convenience system
The convenience system previously used in
the Audi A2 is also used in the Audi A4.

In the series version, the following additional In the basic version without rear electric win-
functions dow lifters, central locking control of the rear
doors is assumed by the central convenience
– Door warning lights electronics.
– Radio remote control

and in the optional version, the following

functions

– Anti-theft alarm with interior monitor and

towing protection (new)
– Electric sliding/tilting/glass sun roof
– Footwell lights
– Exit lights
– Mirror fold-in function
– Mirror memory function

are included in the Audi A4.

Central convenience unit J393

Door control, Door control unit,

driver’s side unit passenger’s side J387
J386

Door control unit, Door control unit,

rear left J388 rear right J389
(optional) (optional)

SSP254_132

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 Central convenience electronics (CCE)

The following information and functions

are processed in the central convenience
electronics:

Sensors Actuators

Crash signal Fuel filler flap

(from airbag control unit J234) – Motor for tank cap locking V155

Handbrake switch F9 Tailgate

– Motor for tailgate release V139
Tailgate release
– Button for release, tailgate lock Anti-theft alarm (optional)
cylinder F248 – Horn for anti-theft alarm H8
– 3. Remote control button (sounder)
– Switch for tailgate to F206 – Turn signal lights via data bus to
– Switch for central locking, tail- vehicle electrical system con-
gate F218 trol unit J519

Anti-theft alarm (optional) Interior light control

– Contact switch for bonnet F266 – Dimming of interior lighting
– Ultrasonic sensor for anti-theft – Footwell light switching
alarm G209 (optional)
– Luggage compartment lamp
Aerial for remote control, switching
Central locking and anti-theft
alarm in multi-communication bar Automatic closing/opening
– Window lifters via door control
Reversing lamp M17 units
– Sun roof
When mechanical window lifters
fitted in rear When mechanical window lifters
– Door contact signal fitted in rear
– Locking signal – Lock rear door lock motors
– Safe signal – Safe rear door lock motors
for rear doors – Activation of rear entry lights
(optional)
– Activation of rear door warning
lights

Enabling of door control units and

sunroof

Gateway function for diagnosis

– Control unit for vehicle electrical
system J519
– Steering column switch module
J527

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 Electrical system

Door control units

The door control units integrated in the

window lifter motors process the following
signals:

Sensors Actuators

Window lifter switches Door locking and unlocking

Enabling via the CCE Safe activation and deactivation of

the doors
Door lock feedback signal
Activation of illumination in the
– Door contact signal doors
– Locked signal
– Safe signal – Entry lights (optional)
– Door opener illumination
for driver’s door also (optional)
– Door warning lights
– Lock cylinder switch unlocking/ – Switch illumination
locking F241
– Interior central locking switch for front doors also
F59
– Switch for childproof lock E254 – Electric mirror adjustment
(optional) – Mirror heating
– Central window lifter operation – Mirror fold-in function
– Mirror adjustment switching E48 – Mirror memory
– Switch for mirror adjustment E43
– Switch for mirror fold-in function for driver’s door also
(optional) E263
– Switch for unlocking luggage – Control of indicator LED
compartment (USA) E164 – Inclination sensor LED switched
– Switch for seat memory, driver’s off (optional)
side (optional) E263 – LED, interior monitoring
– Switch for interior monitor E183 – LED, childproof lock
(optional)
– Inclination sensor switch additionally for passenger's door
(optional)
– Mirror for reversing (optional)
for front doors also

– Mirror release switch (optional)

– Sender for mirror position for
mirror memory (optional)

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 Mirror functions

The mirror heating is switched on together

with the

– rear window heating

– at an outside temperature of below 20 °C

switches on automatically.

When the mirror heating is switched on, the

heating capacity is 100%. Then the heating is
activated intermittently in accordance with
the ambient temperature and vehicle speed. SSP254_126
The mirror glass is kept at a temperature of
around 20 °C.

The mirror fold-in function (optional) returns

the mirrors to the normal position at a vehicle
speed of 15 km/h. The function is disabled at
the same time.

SSP254_127
Passenger’s side mirror

Lowering of the mirror (optional) takes place

when the reverse gear is engaged.

The mirror is returned to its original position

by

– operating the mirror selector switch, or

– when the speed of 15 km/h is exceeded.

SSP254_128
Diagnostics

The adjustment of various settings can be In order to account for the resistance of
performed via the control unit coding and normal or insulating windows with regard to
adaption functions of the convenience the excess force limitation function of the
system diagnosis. electric window lifters, the relevant type of
glazing is set in adaption channel 63.
Customer requirements relating to the
convenience opening and closing functions
can be taken into account via adaption
channel 62.

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 Electrical system

Anti-theft alarm with interior monitor

Door lock

Ignition steering
TS
lock D

Convenience data bus

Central control unit for con-

venience system J393

High and low pitched tones

- air horn (sounder)

SSP254_133

The Audi A4 convenience system is available Deactivation is performed by

with
– opening the vehicle via the radio remote
– Anti-theft alarm control or
– Ultrasonic interior monitor – opening the vehicle via the driver’s door
– Shattered glass sensor (Avant) lock cylinder and switching on the ignition
– Towing protection within 15 seconds. If this time period is not
observed or if the key used is not stored in
as optional extras. the immobiliser, the alarm is triggered.

The anti-theft alarm is only activated when Data exchange between the immobiliser in
the vehicle is locked via the radio remote con- the dash panel insert and the central conven-
trol and by closing the driver's door. ience electronics takes place via the conven-
ience data bus.

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 An innovation in the anti-theft alarm is that a
sounder with an integrated battery is fitted in
place of the horn.

This enables the alarm to sound even when

the power supply has been interrupted.

SSP254_134

The ultrasonic interior monitor and the tow-

ing protection can be switched off from
inside the passenger compartment by means
of a switch.

SSP254_135

Diagnostics

The angles of the both the longitudinal and

transversal inclination of the inclination sen-
sor are displayed in the measured value
block.

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 Electrical system

Functional mechanism of inclination sender

Towing protection is achieved by means of Variously arranged electrodes project into

the inclination sender installed in the central this fluid.
convenience electronics. Alternating fields are applied to the elec-
trodes of the sender, which is divided into
The functional mechanism of the inclination sub-compartments.
sender is based on the determination of When a change in position occurs, the distri-
resistance changes relating to the volumetric bution of the fluid in the chambers also
fluctuation of a viscous electrically conduc- changes.
tive fluid. As the level of the liquid in the sub-compart-
ments changes, the resistance determined for
the sub-compartments via the electrodes also
changes.

SSP254_110

Ceramic
housing
Sub-com-
partment
Indicator
fluid

Electrode Electrodes
connections

Operational
The resistance is stored at the moment of amplifier
activation of the anti-theft alarm.
Changes in the position of the inclination
sensor caused by one-sided lifting of the
vehicle alter the resistance. The alarm is trig-
gered.
The angle of inclination can be displayed in
the measured value blocks.

SSP254_111
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 Radio chorus II, concert II and symphony II

In the new Audi A4, the new generation of

radios, chorus II, concert II and symphony II
are available as options.

The following functions have been optimised:

– AM has been extended to include long

wave.
– There are now 12 programmable stations
for AM and FM.

All three radio versions are compatible with

the external CD changer (optional).

The optional CD changer is now built into the

glove compartment.

LOAD
AIRBAG

COMPAKT
AKT

Audi cd charger DIGITAL

AL AUDIO

OFF ON

SSP254_106
The BOSE sound system can be ordered as an
optional extra for all radio systems of the new
generation.

The connection of the new generation of

radios to the data bus information system
enables the exchange of large volumes of
data with other systems.

This makes new functions such as e.g.

convenience radio coding possible.

Thanks to the convenience radio coding, man-

ual deactivation of the radio anti-theft lock
following a loss of the power supply is no
longer necessary.
A prerequisite is that the radio is built into the
same vehicle.

Sound quality is enhanced by the installation

of a central loudspeaker in the centre of the
dash panel as well as a sub-bass speaker
under the rear shelf.

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 Electrical system

Radio chorus II

New functions with respect to the predeces-

sor model include:

– Skip title function

– Scan function
– Dolby noise suppression

in the cassette player as well as

– a sorting function within a radio station

family
SSP254_009
in the convenience radio tuner search func-
tion.

Radio concert II

A single speed CD player is integrated in the

concert II radio.

The cassette player has been discontinued.

SSP254_007

Radio concert II and symphony II

The improved radio traffic news memory in In order to improve sound quality, acoustic
the Radio concert II and symphony II allows curves related to vehicle type are stored in the
the driver to program the time for starting the concert II and symphony II radios.
two-hour recording of traffic news announce-
ments. Two timers are available, which can be The acoustic curves are set in the control unit
programmed individually. coding function of the radio systems.

Example: In addition, the sound settings for the FM, AM

and CD modes are stored separately in the
The driver can set the starting time for the concert II and symphony II radios. Conse-
recording of radio traffic news announce- quently, the various level controls do not
ments for the drive to work in the morning require resetting each time the driver
and for the drive back in the evening sepa- changes modes.
rately.

Radio reception is improved in the concert II

and symphony II radios by the use of the
Multi Communication Bar (MCB) with inte-
grated aerial diversity.

For further information on the aerial module,

please refer to 72.

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 Radio symphony II

A 6x CD changer as well as a cassette player

are integrated in the symphony II radio.

Searching for alternative frequencies is

speeded up by the use of a second tuner. The
second tuner also allows for Traffic Message
Channel (TMC) evaluation in the background.

For further information, please refer to the

relevant operating instructions.
SSP254_006

CAN networking in the new generation of

radios

All three radio versions are connected to the

data bus information system.

Important signals via the data bus informa-

tion system:

Inputs/source Outputs/receiver

– Ignition on/steering column- – Display functions/dash panel

electronics insert
– Ignition key inserted/steering – Sleep signal/data bus informa-
column electronics tion
– Switch illumination/dash panel – TMC data for symphony II/
insert navigation system
– Display illumination/dash panel – Convenience coding request/
insert dash panel insert
– Speed/dash panel insert
– Convenience coding/dash panel
insert
– Vehicle identification/dash
panel insert
– Prompt signal/data bus informa-
tion
– Data bus system information/
dash panel insert
– Time/dash panel insert
– Control signals from multi-func-
tion steering wheel/steering
column electronics

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 Electrical system

Example:

If the radio is switched on with the ignition

key (S-contact) this requires the exchange of
data between three control units:

– Steering column electronics,

– dash panel insert (gateway) and
– radio.

If the radio does not switch on,

– the signal input in the steering column

electronics (terminal 86S),
– communication between the steering col-
umn electronics and the dash panel
(convenience data bus) and
– communication between the dash panel
and the radio
(data bus information system)

must be checked.

Diagnostics For further information on IF wiring,

please refer to SSP 213, Page 54.
For diagnosis of radio systems concert II and
symphony II, current consumption of aerial
diversity is monitored via the intermittent
frequency (IF) wiring.

Test mode

The new radio versions are equipped with a

test mode. FM 1 DOT + 88.9
34300033 TP AF
Activating field intensity measurement:

– Radio switched off SSP254_119

Button 1 Field intensity -
– Hold down key 1 mean value
– Switch on radio

Activating GALA display volume increase:

GALA 0dB
– Radio switched off
– Hold down key 2
– Switch on radio
SSP254_120
Button 2 Increase in dB

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 Navigation IV and Navigation Plus-D

The new Navigation System IV and Navigation

System Plus-D are equipped with the dynamic
routing system.

The following traffic hold-ups are taken into

account during route planning:

– closed roads
– tailbacks and
– slow-moving traffic.

The system’s sources of information are the

traffic information from the radio stations via
the Travel Message Channel and from the SSP254_129
telematics® (optional) via the telephone
connection.

Once it is switched on, the navigation system

takes account of the traffic messages within a Selectivity area for traffic
radius of approx. 50 km around the vehicle. messages, 50 km
major diversion
If the route planning is activated, any hold-
ups are taken into consideration.

New hold-ups which arise are immediately

accounted for in the routing and the driver is
re-routed.

Data transfer of the traffic data is by

– Travel Message Channel data from the

radio
– Telephone data from the telematics control
unit J526
SSP254_113
to the navigation system via the data bus
information system. Tailback local diversion

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 Electrical system

Within the menu structure of the navigation

system, the driver is able to

– switch the dynamic routing on and off,

– select the source of traffic information,
– manually exclude route sections from the TELE Menu
route planning.

For further information, please refer to the

operating instructions.

RETURN
Travel Message Channel (TMC)

The TMC is a component of the Radio Data

System (RDS), which is transmitted by the NAV INFO
radio stations.

The information in the TMC includes the loca-

tion, type and duration of traffic hold-ups
reported by the police, automobile associa-
tions and government authorities in a coded
form standard throughout Europe.
1 Traffic information is available.
The TMC data is not currently transmitted by Source: Radio
all radio stations. Alternative route Traffic information
This requires the use of a second tuner in the
radio or in the interface of the Navigation now automatic read
System Plus.
for route section interrogate latest
As only the symphony II radio is equipped
with a second tuner, the use of TMC data for for route from here
dynamic routing is only possible with this
Settings
version.

Dynamic routing in conjunction with the

chorus II and concert II radios is only possible Tailback function Back with RETURN
by means of the traffic messages via tele-
phone with telematics®. SSP254_130

Diagnostics

The navigation system diagnostics is interro-

gated via the L-wire.

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 Interface for Navigation Plus (R94)

The interface of the Navigation System Plus

performs the following tasks:

– Exchange of data bus information -

Navigation System Plus internal data bus
– Transfer of TMC data to the Navigation
System Plus for dynamic route planning

In order to receive the TMC data, an interface

connects the aerial and radio.
SSP254_122

The following data is exchanged via the

interface:

Input from data bus Output to data bus

information/sender information/receiver

Display request/instrument cluster Display/instrument cluster

Traffic news/Telematics Control signals data bus/data bus

information system
Fault messages/card reader
Vehicle data/card reader
Control signals/multi-function
steering wheel

Terminal 15/steering column

electronics

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 Electrical system

Multi-communication bar (MCB)

The Audi A4 Saloon features the multi-com-

munication bar in the top part of the rear win-
dow for the first time.

The

– aerial module,
– aerial for navigation system (GPS),+
– and aerial for telephone (GSM)

are fitted in the MCB.

The SSP254_109
GPS
GSM
– aerial diversity,
Aerial module
– aerial amplifier for the four radio aerials
(FM1-4, AM),
– 4 aerial amplifiers for the TV aerials 1-4,
– aerial for radio remote control, central lock-
ing (RCL),
– and the aerial for the telestart function (TS)
of the auxiliary heating
TS
are integrated in the aerial module.

The aerial conductor is located in the rear

window. The electrical connection between
the aerial amplifier and the conductor on the
rear window is made by means of spring
contacts.

Both the GPS and the GSM aerials are also Normal glazing
fitted in the top edge of the rear window, but
these are not connected by means of conduc-
tors in the rear window.
TS
Thanks to this compact arrangement, no
aerials are visible from outside.

The emergency aerial for the telematics is

located at the rear bumper.

Insulating glazing
SSP254_013

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 Television (TV) tuner

The image and sound quality of each individ-

ual tuner is monitored in the TV tuner. The
tuner with the best reception is switched
through to the operating unit.

Thanks to the high speed, switching can be

performed within a single scanning line.

The control signals of the Navigation Plus -

operating unit are transmitted via the data
bus system of the navigation system.

Transfer of the image and sound data takes

place via the conventional wiring. SSP254_137

The TV tuner is not connected to the data bus

information system.

Self-diagnosis
Address word 57

The video standard for the relevant country

can be set via the coding function.

The TV aerials can be activated for reception

consecutively in the final control diagnosis,
enabling the detection of a faulty aerial.

The condition of the connections to the

aerials, navigation system and external video
inputs can be displayed via the measured
value blocks.

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 Electrical system

The electronic logbook, Audi Logbook

The Audi Logbook is a fully automatic logbook

which allows the customer to calculate
business and private journeys in order to
determine costs, e.g. for tax purposes.

The Audi Logbook is only available in

conjunction with Navigation Plus or
Navigation IV.
SSP254_065
CAN bus information
+ -

The Audi Logbook System includes: For initial operation of the Audi Logbook, the
chip card must be activated using a PC and
– Chip card reader R99, PC card reader (see Owner's manual).
– PC card reader,
– Software CD for installing the Audi
Logbook program on the PC,
– Chip card.

SSP254_040

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 In the ”business journey” mode, data relating
to

– date
– time at start of journey
– position at start of journey
– position at end of journey
– time at end of journey
– kilometres driven

are stored in the Chip card reader R99.

The date and route driven are stored In the

”private journey” mode.

The ”continue journey” mode is used to pre-

vent short breaks from being stored (e.g. refu-
elling stops).
Select purpose of journey:

Back
Operation and setting of the Audi Logbook is
Business journey
via the navigation system menu.
Private journey
The following options can be selected:
Continue, business
– Business journey
Continue, private
– Private journey
– Continue journey Memory occupancy 0 %

LOGBOOK Back with RETURN

SSP254_131

Around 250 individual journeys can be stored The Audi Logbook has no diagnostic
on the chip card. capability.
Once 200 individual journeys have been
stored in the card reader, the driver is Fault messages are indicated via the naviga-
requested by a message on the navigation tion system display.
system display to store the data on the chip The messages displayed are generated in the
card. chip card reader and communicated to the
navigation system as information via the data
The card reader has the capability to store bus.
around 2700 individual journeys.
In order to activate the Audi Logbook,
adaption of the navigation unit must be
performed. (see workshop manual).

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 Heater/AC

Design and function

The air conditioner represents a further devel- The redesigned system is based on the
opment of the two-zone air conditioning performance data for top of the medium
concept previously used in the A6. range vehicles, taking account of low system
weight and energy consumption as well as, to
an increasing extent, recycling capability.

Operating and display unit E87.

SSP254_032

Innovations include:

– Individual temperature control for both – Integrated rotary control knob with poten-
driver and front passenger tiometer for seat heating.
– Option of synchronising the temperature (this means the potentiometers cannot be
zones for driver and front passenger by replaced individually)
pressing the ”Auto” button for approx. – Intake blower V42 for passenger compart-
three seconds. ment temperature sensor G56 is integrated
and cannot be replaced individually.
Example:
If the same temperature is desired for the A distinction is made between eight different
passenger’s side as for the driver’s side, versions, identified by means of the part
the ”Auto” button should be pressed for at number index:
least three seconds.
The same applies the other way round, for – with or without seat heating
making the driver’s side temperature the – with or without navigation system,
same as that of the passenger’s side. – at a later date, with or without air quality
sensor.
– The fault diagnosis and measured value
blocks for the seat heating system are read
out via address word 08 for the air condi-
tioner. The operating and display unit E87 is
– The system is encoded automatically via connected to the convenience CAN bus.
the dash panel insert. Diagnosis takes place via the K-wire.

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 7-piston compressor

SSP254_033

Two versions of externally controlled com- Distinguishing features to identify the com-
pressors are used in the Audi A4: pressor fitted are:

– the 6-piston compressor, which you have – Lettering on the compressor identification
already studied in detail in SSP 240, plate is 6SEU for the 6-cylinder or 7SEU for
– the 7-piston compressor, which differs in the 7-cylinder compressor.
the number of pistons and the resulting – the greater outer diameter of the
increased displacement. 7-cylinder compressor (approx. 122 mm)
compared to the smaller outer diameter of
Depending on the country-specific vehicle the 6-cylinder compressor
version, the 7-piston compressor with its (approx. 113 mm)
higher total output is used (e.g. in hot coun-
tries).

Based on the engine version installed, a dis-

tinction is made between the following com-
pressor Vehicles equipped with a 7-piston
types: compressor, are fitted with a radiator fan
which has a higher output.
– 6 and 7 pistons for compressor fitted on
right side of engine,
– 6 and 7 pistons for compressor fitted on
left side of engine,
– 6 pistons for 6-cylinder TDI Diesel mechani-
cal units.

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 Heater/AC

Air conditioner
Flaps for
Defrost flap control Central flap
centre vent Temperature
Defrost motor V107 control motor V70 sensor - fresh air
flaps intake channel G89

Temperature Fresh air/air-

flap (upper) flow flap

Recircula-
ted-air flap

Air recirculation
Left temperature flap control
Right tempera- motor V113
flap control ture flap control
motor V158 motor V159 Motor for air flow
flap V71

Sender for outlet

temperature,
Temperature evaporator G263
flap (lower)

Flaps for footwell Footwell vent tempera- Footwell vent tempera-

vent ture sender (left) G261 ture sender (right) G262

Vent temperature
sender
left right
G150 G151
SSP254_019

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 The basic functions of the air conditioner in
the Audi A4 are based on the Audi A6 system
and includes the following features:

– Air-side separation for driver’s and passen-

ger’s side.
– The heat exchanger can be replaced with-
out removing the air conditioner.
– The PTC additional heater element for die-
sel mechanical units can also be replaced
without removing the unit.
– All control motors and potentiometers are
easily accessible and replaceable.
– Connecting hose from air conditioner to
glove compartment for supplying the glove
compartment cooler (optional).
(in vehicles without glove compartment Rotary valve SSP254_015
cooling, the connection is sealed with a
rubber plug). Connecting hose to glove
compartment cooler
– Modified fresh air blower for passenger
compartment (description, see section:
Fresh air blower/electronically controlled
fresh air blower, on page 81).

Glove compartment cooling

The cooler fills the entire space of the glove

compartment. It can, for instance, hold two
bottles with a volume of 0.25 and 0.7 litres.
The cold air supply is achieved via a connect-
ing hose from the air conditioner unit.
The hose is fitted with a rotary slide for cold
air regulation.

Two examples give an impression of its per-

formance:

– Cooling of the cooler contents from

approx. +30 °C to approx. +16 °C within one
hour and
– after switching off the cold air supply,
warming up by approx. +4 °C per hour at an
ambient temperature of approx.
+30 seconds and exposure to the sun. SSP254_034

79

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 Heater/AC

Solar roof

Solar generator
Ventilation

Air conditioner
with control
system

Contacts
SSP254_035

For the first time, the A4 can optionally be Significant advantages in comparison with
equipped with the solar roof previously used vehicles without solar roof are:
in the A8 and A6.
The fresh air blower is continually driven by
– lowered temperature level in vehicles
electricity obtained from solar radiation. parked in the sun (see chart),
The output is proportional to the intensity of
– increased efficiency of the air conditioner
the sunlight. as the interior temperature set is achieved
more quickly,
Modifications to the familiar models: – despite the reduced output of the system
during the winter, an air-drying effect
– Re-engineered fresh air blower occurs which effectively dehumidifies the
– The DC/DC transformer has been discontin- vehicle, reducing fogging of the windows.
ued, its function is now performed by the
fresh air blower control unit J126.

Heating without solar

Heating with solar

Global radiation
Radiation [W/m2]
Temperature [°C]

SSP254_036
Time [min]
80

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 Fresh air blower

Control technology has been integrated in the In the case of malfunctions, such as e.g. a stiff
new fresh air blower. or blocked blower, this is signalled to the
operating and display unit E87 by duty cycle
It includes the following features: changes based on the altered frequency. The
relevant fault is set.
– Integrated control unit with diagnostic
capability via the operating and display The blower bearings have been re-engineered
unit E87 (fault memory and measured in order to optimise the effectiveness of the
value block diagnosis-capable control system.
unit), This particularly benefits solar operation.
– optimised bearings for smoother running,
– separate solar input. The energy supplied by the solar roof is
utilised to drive the fresh air blower by means
The required blower speed is calculated in the of special electronics via the separate solar
operating and display unit E87, and requested input in the blower.
by the control unit for fresh air blower J126
via a PWM signal.

SSP254_037
81

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 Heater/AC

Actuators/sensors

Ambient temperature sensor

G17

Dash panel temperature

sensor G56
and
N
ECO

OFF

Temperature selection in the air condi-

tioner operating and display unit E87

Sender for footwell vent temperature,

right, G262

Sender for footwell vent tempera-

ture, left, G261

Vent temperature sender, right, G151

Vent temperature sender, left, G150

Fresh air intake temperature

sensor G89

Evaporator outlet temperature

sender G263

High-pressure sender G65

Sunlight penetration photo-

sensor G107

Signals:
Terminal 31b from automatic wash/wipe interval system
Regulating valve for air conditioner compressor N280
Air quality sensor G238

82

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 Automatic gearbox
control unit J217
Motronic control unit J220

Control unit with display in dash

9:36
28.07.2000
km 153.9
5244
panel insert J285

Diagnosis interface for data bus

J533 (gateway)

Diagnosis connection

Radiator fan control unit J293

Control unit
for air conditioner Radiator fan V7

Regulating valve for air con-

ditioner compressor N280

Central flap control motor V70 and

potentiometer G112

Defrost flap control motor V107 with

potentiometer G135

Motor for air flow flap V71 with

potentiometer G113

Temperature flap positioning motor V158

(right) with potentiometer G221

Air recirculation flap control motor V113

for potentiometer G143

Temperature flap control motor V158

(left) with potentiometer G220

Series resistor for fresh air blower N24,

control unit for fresh air blower J126 with
fresh air blower V2

Signals:
ECON signal
Engine speed increase
SSP254_041 Air conditioner compressor
83

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 Heater/AC

Functional diagram
for fully automatic air
conditioner
Components

C20 Solar cells Z1 Heated rear window

E87 Operating and display unit for Z6 Heated driver’s seat
air conditioner Z8 Heated front passenger’s seat
G59 Driver’s seat temperature sensor
G60 Front passenger’s seat temperature
sensor
G65 High-pressure sender
G89 Temperature sensor - fresh air intake-
channel
G107 Sunlight penetration photosensor
G112 Potentiometer in positioning motor
for central flap
G113 Potentiometer in positioning motor
for air flow flap
G135 Potentiometer in central flap control
motor defrost flap Colour coding
G143 Potentiometer in central flap control
motor recirculated-air flap = Input signal
G150 Vent temperature sender, left
G151 Vent temperature sender, right = Output signal
G220 Potentiometer, positioning motor for
temperature flap, left = Positive power supply
G221 Potentiometer, positioning motor for
temperature flap, right = Earth
G238 Air quality sensor
G262 Vent temperature sender, footwell, = CAN-BUS
left
G262 Vent temperature sender, footwell,
right
Auxiliary signals
G263 Vent temperature sender, evaporator
J9 Relay for heated windscreen and
rear window 1 CAN-high convenience
J126 Blower control unit
N280 Regulating valve for compressor, 2 CAN-low convenience
air conditioner
S Fuses 3 Terminal 75
V2 Fresh air blower
V70 Central flap control motor 4 Windscreen heating Z2
V71 Air flow flap control motor
V107 Defrost flap control motor
V113 Air recirculation flap control motor K-diagnostic connection
V158 Temperature flap positioning motor,
left
V159 Temperature flap positioning motor, CAN-H CONVENIENCE { Connection to
right
convenience data
CAN-L CONVENIENCE bus

84

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 15 30
J9

S6 S25 S1 S26 S44

5A 30A 5A 30A 30A

G238 G65 Z1 Z6 Z8 V2/J126 C20 G107

N280 G59 G60 G150 G151
M

°t °t °t °t

E87

t° t° t° t° 1 2 3 4

G112 G113 G135 G143 G220 G221 G89 G261 G262 G263

M M M M M M

V70 V71 V107 V113 V158 V159

31 31

in out

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 Heater/AC

Additional heater

Control and heater

unit for heating
system J162 Heating system
heat exchanger

Glow plug
-+
Combustion chamber

K
Combus- Exhaust
tion air gas

Fan
drive Diffuser
Flame sensor

Fuel pump
Fuel tank

SSP254_023

The Audi A4 can optionally be equipped with

an additional heater for coolant.
Its mode of operation corresponds to the
systems in use previously.
The additional heater warms the heating-
system heat exchanger in the air conditioner
unit via the cooling-water circuit.

The cut-in time is ”programmed” via the dash

panel insert.

SSP254_097

86

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 87

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