2000 Audi TT

2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

2000-2004 ENGINE PERFORMANCE

Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC & AWP - TT

TURBOCHARGER, G-CHARGER
CHARGE AIR SYSTEM WITH TURBOCHARGER

WARNING: Observe the following for all installations, especially in engine

compartment due to lack of room:

z Route lines of all types (for example, for fuel, hydraulic, EVAP
canister system, coolant and refrigerant, brake fluid, vacuum) and
electrical wiring so that the original path is followed.
z Watch for sufficient clearance to all moving or hot components.
z Switch on passenger-side airbag again after completing work.

Turbocharger with attachments, removing and installing

Observe RULES OF CLEANLINESS .

NOTE: z Always replace self-locking nuts, bolts which have been tightened to
tightening torque as well as gaskets and O-rings.
z Secure all hose connections using hose clamps appropriate for the model
type:

See Parts Catalog.

z Before performing a test or repair, check all hoses and wires for secure
fitting and proper seal.
z Charge air system must be properly sealed.
z Charge pressure hoses and their connections must be free of grease
before re-installation.

Assembly overview

Part I

NOTE: Always replace seals.

NOTE: The following list refers to items in Fig. 1 .

1. - Front exhaust pipe

Helpmelearn
January-06-08 12:27:05
12:26:59 PM Page 1 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

2. - 40 Nm
z replace

3. - Spacer sleeve
4. - Seal
z replace

5. - 10 Nm
z use fluid securing material D 000 600 A2 to insert.

6. - Vacuum diaphragm
z For boost pressure regulator valve

7. - Fuse
8. - Turbocharger
z Boost pressure regulation, checking, see BOOST PRESSURE SYSTEM, CHECKING

9. - O-ring
z replace

10. - 10 Nm
11. - Connection
12. - Seal
z replace

z Note installed position

13. - 20 Nm
14. - Heat shield
15. - 10 Nm
16. - Banjo fitting -30 Nm
17. - Oil supply line
z From oil filter bracket

18. - 30 Nm
z replace

z Coat threads and bolt head contact surface with G000500

19. - Exhaust manifold

20. - Seal
z replace

z Note installed position

21. - 20 Nm
22. - Banjo fitting -30 Nm
23. - 25 Nm
z replace

24. - Banjo fitting -35 Nm

Helpmelearn
January-06-08 12:26:59 PM Page 2 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

25. - Coolant return line

26. - 25 Nm
27. - Spacer sleeve
28. - Banjo fitting -35 Nm
29. - 10 Nm
30. - Coolant supply line
31. - Banjo fitting -35 Nm
32. - Bracket
33. - 30 Nm
z only use original equipment bolts

See Parts Catalog.

34. - 25 Nm
35. - Seal
z replace

36. - Seal
z replace

37. - 10 Nm
38. - Oil return line
z To oil pan

39. - 10 Nm
40. - 10 Nm
z use fluid securing material D 000 600 A2 to insert.

Fig. 1: Exploded View Of Exhaust Manifold And Turbocharger With Attachments (Part I)
Courtesy of AUDI OF AMERICA, INC.
Helpmelearn
January-06-08 12:26:59 PM Page 3 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Part II

NOTE: The following list refers to items in Fig. 2 .

1. - To boost pressure regulator valve

2. - Retaining clip
3. - O-ring
z replace

4. - Intake air hose

z to connection on turbocharger

5. - Wastegate Bypass Regulator Valve -N75-

z Check activation. See WASTEGATE BYPASS REGULATOR VALVE, CHECKING .

6. - Mechanical recirculation valve

z Checking, see DECELERATION SHUT-OFF VALVE, CHECKING

7. - Hose
z to Recirculating valve for turbocharger -N249-

8. - Pressure regulator valve

z For crankcase ventilation

9. - Hose
z from mechanical recirculation valve to upper air guide pipe

10. - to crankcase breather valve

11. - upper air guide pipe
12. - 25 Nm
13. - 25 Nm
14. - to throttle valve connections
15. - Check-valve
z Installation position (light/dark side): As shown in illustration

16. - to Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80-

17. - Hose
18. - Check-valve
z Installation position (light/dark side): As shown in illustration

19. - Coolant line

20. - to connection on turbocharger
21. - to vacuum diaphragm for boost pressure regulator valve

Helpmelearn
January-06-08 12:26:59 PM Page 4 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Fig. 2: Exploded View Of Turbocharger With Attachments (Part II)

Courtesy of AUDI OF AMERICA, INC.

Parts of charge air cooler, removing and installing

NOTE: z All hose connections are secured with clamps.

z Charge air system must be properly sealed.
z Note assembly markings at hoses and components during installation.

NOTE: The following list refers to items in Fig. 3 .

1. - Air duct
2. - Charge air cooler
3. - Charge Air Pressure Sensor -G31-
z Checking, see CHARGE AIR PRESSURE SENSOR, CHECKING

4. - 10 Nm
5. - Rubber grommet
z With sleeve

6. - 10 Nm
7. - Hose
z between intake manifold and charge air cooler

8. - Rubber grommet
z With sleeve

9. - Hose
z between upper and lower air guide pipe

10. - 10 Nm
11. - lower air guide pipe
Helpmelearn
January-06-08 12:26:59 PM Page 5 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

12. - 10 Nm
13. - Bracket
14. - Rubber grommet
z With sleeve

15. - Hose
16. - 10 Nm

Fig. 3: Exploded View Of Charge Air Cooler

Courtesy of AUDI OF AMERICA, INC.

Overview of turbocharging system

NOTE: The following list refers to items in Fig. 4 .

1. - From fuel tank

2. - EVAP canister
z with Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80-

3. - Check-valve for EVAP canister

z between EVAP canister and intake manifold before turbocharger

z Installation position (light/dark side): Arrow points in direction of aperture, as shown in figure.

4. - Turbocharger
z Boost pressure regulation, checking, see BOOST PRESSURE SYSTEM, CHECKING

5. - Vacuum diaphragm for boost pressure regulation

6. - Mechanical recirculation valve
z Checking, see DECELERATION SHUT-OFF VALVE, CHECKING

7. - Brake booster

Helpmelearn
January-06-08 12:26:59 PM Page 6 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

8. - Check-valve
z Between brake booster and intake manifold

z Installation position (light/dark side): Arrow points in direction of aperture, as shown in figure.

9. - Wastegate Bypass Regulator Valve -N75-

z Check activation. See WASTEGATE BYPASS REGULATOR VALVE, CHECKING .

10. - Mass Air Flow (MAF) Sensor -G70-

11. - Air filter housing
12. - Pressure regulator valve for crankshaft housing ventilation
13. - Vacuum reservoir
z Bolted on at cylinder head

14. - Fuel pressure regulator

15. - Intake manifold
z with Intake Air Temperature (IAT) Sensor -G42-

16. - Check-valve
z Installation position (light/dark side): Arrow points in direction of aperture, as shown in figure.

17. - Recirculating valve for turbocharger -N249-

z Checking, see RECIRCULATING VALVE FOR TURBOCHARGER, CHECKING

18. - Secondary Air Injection (AIR) Solenoid Valve -N112-

19. - Crankcase ventilation
20. - Secondary Air Injection (AIR) Pump Motor -V101-
21. - Throttle Valve Control Module -J338-
22. - Charge air cooler
z with Charge Air Pressure Sensor -G31-

23. - Check-valve
z between EVAP canister and intake manifold

z Installation position (light/dark side): Arrow points in direction of aperture, as shown in figure.

Helpmelearn
January-06-08 12:26:59 PM Page 7 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Fig. 4: Overview Of Turbocharging System Components With Vacuum Diagram

Courtesy of AUDI OF AMERICA, INC.

Rules of cleanliness

When working on turbocharger, carefully observe the following "5 Rules of Cleanliness":

z Thoroughly clean all connections and the surrounding area before disconnecting.
z Place parts that have been removed on a clean surface and cover. Use lint-free cloths only!
z Carefully cover over opened components or seal, if repairs are not performed immediately.
z Only install clean components:Only unpack replacement parts immediately prior to installation. Do not
use parts that have been stored loose (in tool boxes etc.)
z When the system is open: Do not work with compressed air if it can be avoided. Do not move vehicle
unless absolutely necessary.

Safety precautions

If special testing equipment is required during road test, note the following:

Audi TT Coupe:

z Test equipment must always be secured to the rear seat and operated from there by a second person.

If test and measuring equipment is operated from the passenger seat, the person seated there could be
injured in the event of an accident involving deployment of the passenger -side airbag.

Audi TT Roadster:

z Deactivate the passenger-side airbag using the key switch in the glove compartment or via On Board
Diagnostic (OBD).
z Switch on passenger-side airbag again after completing work.
Helpmelearn
January-06-08 12:26:59 PM Page 8 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

BOOST PRESSURE SYSTEM, CHECKING

Boost pressure regulation, checking

Recommended special tools and equipment

z V.A.G 1397 A Turbocharger Tester

Fig. 5: Identifying V.A.G 1397 Turbocharger Tester

Courtesy of AUDI OF AMERICA, INC.

Test requirements

z No leaks on intake or exhaust side.

z Engine oil temperature at least 80 °C.

Test sequence

WARNING: To reduce the risk of accident during road tests, always observe safety
precautions. See SAFETY PRECAUTIONS .

Charge pressure is measured under Wide Open Throttle (WOT) while driving or on the roller type test stand.

z Using VAG1397A Turbocharger Tester test hose, connect T-piece to front of intake manifold.

Helpmelearn
January-06-08 12:26:59 PM Page 9 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Fig. 6: Connecting VAG1397/A Turbocharger Tester To Front Of Intake Manifold

Courtesy of AUDI OF AMERICA, INC.

z Guide test hose over rear corner of hood and through right window into vehicle interior.
z Turn turbocharger tester on and select measuring range (absolute pressure).

Fig. 7: Identifying VAG1397/A Turbocharger Tester

Courtesy of AUDI OF AMERICA, INC.

z Connect test hose to connection flange.

NOTE: z Using turbocharger tester, see operating instructions.

z Hoses must be connected so there is no possibility of leaks, otherwise
incorrect readings may result.
z Ensure test hose is not pinched at hood and side window.
z By pressing memory button "M" on turbocharger tester, the last test value
Helpmelearn
January-06-08 12:26:59 PM Page 10 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

is saved until either memory button "M" is pressed again or the

turbocharger tester is shut - off.
z A blinking comma in display field indicates a value has been saved.
z An arrow appears in the top left corner of display field if turbocharger
tester battery voltage drops below the permissible specification.
z Before testing drive vehicle rapidly at least 3 km (without frequent stops
and similar).
z A second technician is required because the indicated values must be
read out during vehicle operation.

z Accelerate vehicle in 3rd gear at full throttle from 2000 RPM and watch tachometer.
z At 3000 RPM press memory button "M" on VAG1397A.

Fig. 8: Identifying VAG1397/A Turbocharger Tester

Courtesy of AUDI OF AMERICA, INC.

z Specification on VAG1397A: 1.700 ... 1.900 bar positive pressure

NOTE: Repeat measurement if full charge pressure has not yet built up.

If boost pressure is exceeded:

z Check Wastegate Bypass Regulator Valve -N75-. (Throughput in hose from turbocharger via valve to
vacuum diaphragm with connector disconnected)
z Check for proper seating of vacuum diaphragm for wastegate bypass regulator valve at turbocharger.
z Check vacuum diaphragm. See VACUUM DIAPHRAGM FOR WASTEGATE BYPASS
REGULATOR VALVE, CHECKING .
z Check bearing for shaft of wastegate bypass regulator valve in turbocharger for ease of movement. If
rusted solid, replace turbocharger.
Helpmelearn
January-06-08 12:26:59 PM Page 11 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

If boost pressure is not reached:

z Check Wastegate Bypass Regulator Valve -N75-.

z Check bearing for shaft of wastegate bypass regulator valve in turbocharger for ease of movement. If
rusted solid, replace turbocharger.
z Turbocharger faulty, replace.

Wastegate bypass regulator valve, checking

Recommended special tools and equipment

z VAG1526 multimeter or VAG1715 multimeter

z VAG1594 connector test kit

Test sequence

z Switch ignition off.

z Disconnect connector at solenoid valve for boost pressure regulation.

Helpmelearn
January-06-08 12:26:59 PM Page 12 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Fig. 9: Measuring Solenoid Valve For Boost Pressure Regulation Resistance

Courtesy of AUDI OF AMERICA, INC.

z Measure resistance between terminals of valve.

Specified value: 25...35

Helpmelearn
January-06-08 12:26:59 PM Page 13 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

If specified value is not obtained:

z Replace Wastegate Bypass Regulator Valve -N75-.

Vacuum diaphragm for wastegate bypass regulator valve, checking

Recommended special tools and equipment

z VAG1526 multimeter or VAG1715 multimeter

z VAG1594 connector test kit

Test requirement

z Engine oil temperature at least 80 °C.

Test sequence

z Disconnect connector at Wastegate Bypass Regulator Valve -N75-(-1-). See Fig. 10 .

Fig. 10: Identifying Operating Rod

Courtesy of AUDI OF AMERICA, INC.

z Start engine and increase speed to maximum RPM by depressing accelerator pedal suddenly. Operating
rod - 2- for wastegate bypass regulator valve must move.

If operating rod does not move:

z Check lever for wastegate bypass regulator valve -1- for ease of movement. If rusted solid, replace
turbocharger.

If operating rod does not move despite freely moving lever:

Helpmelearn
January-06-08 12:26:59 PM Page 14 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

z Check Wastegate Bypass Regulator Valve - N75-. (Throughput in hose from turbocharger via valve to
vacuum diaphragm with connector disconnected)

If solenoid valve is OK:

z Replace turbocharger, item no. 8 .

Deceleration shut-off valve, checking

Recommended special tools and equipment

z VAG1390 hand vacuum pump

Fig. 11: Identifying VAG1390 Hand Vacuum Pump

Courtesy of AUDI OF AMERICA, INC.

Test requirement

z Performance deficiency or tip-in shocks

Test sequence

NOTE: The deceleration shut-off valve is located in front of the turbocharger. It is

opened by vacuum during deceleration and at idle.

z Attach VAG1390 vacuum pump to recirculation valve.

Helpmelearn
January-06-08 12:26:59 PM Page 15 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Fig. 12: Attaching VAG1390 Vacuum Pump To Recirculation Valve

Courtesy of AUDI OF AMERICA, INC.

z Operate vacuum pump.

z Recirculation valve must open (arrow)

z After approx. 30 seconds, operate vent valve on vacuum pump.

z Recirculation valve must close (arrow)

If recirculation valve does not open or close or valve plate does not seal correctly when valve is closed:

z Replace recirculation valve. Secure connections of recirculation valve using screw clamps.

Charge air pressure sensor, checking

Recommended special tools and equipment

z VAG1526 multimeter or VAG1715 multimeter

z VAG1594 connector test kit
z Wiring diagram

Checking voltage supply and wiring to control module

z Switch ignition off.

z Disconnect connector at charge air pressure sensor.
z Use adapter cables from VAG1594 to connect multimeter to terminals 1 + 3 of connector for voltage
measurement.

Helpmelearn
January-06-08 12:26:59 PM Page 16 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Fig. 13: Identifying Charge Air Pressure Sensor Harness Connector Terminals
Courtesy of AUDI OF AMERICA, INC.

z Switch ignition on.

Specified value: at least 4.5 V

z Switch ignition off.

If specified value is not obtained:

z Connect VAG1598/31 test box to control module wiring harness. Engine Control Module (ECM) is not
connected.

Fig. 14: Connecting VAG1598/31 Test Box To Control Module Wiring Harness
Courtesy of AUDI OF AMERICA, INC.

Helpmelearn
January-06-08 12:26:59 PM Page 17 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

z Check for open circuits in wires between test box and connector according to wiring diagram.

Terminal 1+socket 108

Terminal 3 + socket 98

Terminal 4 + socket 101

Wire resistance: max: 1.5

Fig. 15: Identifying Charge Air Pressure Sensor Harness Connector Terminals
Courtesy of AUDI OF AMERICA, INC.

z Check wires for short circuit to each other.

If no malfunctions are found in the wires and there was voltage between terminals 1 + 3:

z See CHECKING FUNCTION .

If no malfunctions are found in wires and there was no voltage between terminals 1 + 3:

z Replace Motronic Engine Control Module (ECM) -J220-. See REPLACING ENGINE CONTROL
MODULE (ECM) .

Checking function

z Connect test box to control module wiring harness. See CONNECT TEST BOX FOR WIRING
TEST .
z Re-connect connector at Charge Air Pressure Sensor -G31-.
z Connect multimeter to socket 101 and socket 108 for voltage measurement.
z Start engine and measure voltage.
Helpmelearn
January-06-08 12:26:59 PM Page 18 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Specified value: 1.80 to 2.00 volts

z Bring engine to RPM by depressing accelerator pedal suddenly.

Specified value: 2.00 to 3.00 volts

If specified values are not obtained:

z Replace the Charge Air Pressure Sensor - G31-.

Recirculating valve for turbocharger, checking

NOTE: Valve opens between connection to intake manifold and connection to

deceleration shut -off valve with no voltage. Connection to vacuum reservoir is
closed.

Test sequence

z Switch ignition off.

z Disconnect connector from Recirculating valve for turbocharger -N249-.

Helpmelearn
January-06-08 12:26:59 PM Page 19 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Fig. 16: Measuring Recirculating Valve For Turbocharger Resistance

Courtesy of AUDI OF AMERICA, INC.

z Measure resistance between terminals of valve.

Specified value: 27...30 ohm

If specified value is not obtained:

z Replace Recirculating valve for turbocharger -N249-.

If specified values are obtained:

z Connect test box to control module wiring harness. See CONNECT TEST BOX FOR WIRING
Helpmelearn
January-06-08 12:26:59 PM Page 20 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

TEST .
z Check wire between test box socket 105 + 2-pin connector terminal 2 for open circuit according to wiring
diagram.

Wire resistance: max: 1.5 ohm

Helpmelearn
January-06-08 12:26:59 PM Page 21 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

Fig. 17: Identifying Recirculating Valve For Turbocharger Harness Connector Terminals
Courtesy of AUDI OF AMERICA, INC.

z Also check the wire for short circuit to B+ and Ground (GND).
Helpmelearn
January-06-08 12:26:59 PM Page 22 © 2005 Mitchell Repair Information Company, LLC.
 2000 Audi TT
2000-2004 ENGINE PERFORMANCE Turbocharger, G-Changer, Generic Scan Tool: 1.8L Turbo, AMU, BEA, ATC &
AWP - TT

If no malfunctions are found in wire:

z Check wire between 2-pin connector terminal 1 and the Fuel Pump (FP) Relay -J17- for open circuit
according to wiring diagram.

Wire resistance: max: 1.5 ohm

If no malfunctions are found in wires:

z Replace Engine Control Module (ECM). See REPLACING ENGINE CONTROL MODULE (ECM) .

Helpmelearn
January-06-08 12:26:59 PM Page 23 © 2005 Mitchell Repair Information Company, LLC.