AUDI A4 1999 B5 / 1.G AWM Engine Charge Pressure Leak Test Owner's Manual

21-31
If the LED does not light up:

- Check wiring from contact 1 on connector via
fuse to fuel pump relay for an open circuit:

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
- Repair open circuit, if necessary.
If the LED lights up:

- Check actuation.

Checking actuation

- Connect voltage tester VAG 1527 B to contacts 1 (positive) and 2 of
connector.
- Initiate output Diagnostic Test Mode (DTM) and activate recirculatiing
valve for turbocharger -N249-.
The LED must flash.
Pa
ge 21 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
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play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2

21-32
If the LED lamp does not flash or if it lights up
continuously:

- Connect VAG 1598/31 test box to wiring
harness leading to engine control module;
engine control module should not be connected:

Repair Manual, 1.8 Liter 4
-Cyl. 5V Turbo Fuel
Injection & Ignition, Engine Code(s): AWM, Repair Group 24


If the wiring is OK: - Check for open circuit and short to positive or Ground in following
wiring connection: Connector
Contact
Test box VAG 1598/31
2 105
- Repair any open/short circuit as necessary.
- Replace engine control module.
Pa
ge 22 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2

21-33


Wastegate Bypass Regulator valve -N75-,
checking

Special tools and equipment

VAG 1526 A
VAG 1527 B
VAG 1594 A
VAG 1598/31
VAS 5051 with VAS 5051/1
- or
VAG 1551 with VAG 1551/3 A
Pa
ge 23 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2

21-34

Test requirements:

Vehicle diagnostic, testing and information
system VAS 5051 or VAG 1551 Scan Tool
connected.

Test sequence

Note:
The Wastegate Bypass Regulator valve -N75-
and the wiring connections are monitored by the
engine control module.

- Read Diagnostic Trouble Code (DTC) memory
of engine control module.
If a DTC relating to the Wastegate Bypass
Regulator valve -N75 is displayed:

- Disconnect hoses from valve but leave electrical
connector attached.

- Connect auxiliary hose to valve connector marked with an arrow.
- Initiate output Diagnostic Test Mode (DTM) and actuate Wastegate
Bypass Regulator valve -N75-.
Pa
ge 24 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2

21-35

Output Diagnostic Test Mode -N75- waste
gate b
ypass re
gulator valve

Display
If the injector does not click:
If valve does not open or close properly:
Checking internal resistance
The valve must click ... ... and must open and close (check by blowing into the auxiliary
hose).
- Check internal resistance of valve.
- Replace Wastegate Bypass Regulator valve -N75-.
- Disconnect connector from valve.

If specified value is not attained:
If specified value is attained: - Connect multimeter to injector to measure resistance.
Specified value: 25 to 35
- Replace Wastegate Bypass Regulator valve -N75-.
- Check power supply.
Pa
ge 25 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2

21-36

Checking power supply

Test requirements:

Fuse for wastegate bypass regulator valve
OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder

Fuel pump relay OK.

Repair Manual, 1.8 Liter 4
-Cyl. 5V Turbo Fuel
Injection & Ignition, Engine Code(s): AWM, Repair Group 24


- Connect voltage tester VAG 1527 B as follows:Connector
contact
Measure to
1 Engine Ground
- Operate starter briefly.

LED must light up.
Pa
ge 26 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2

21-37
If the LED does not light up:

- Check wiring from contact 1 on connector via
fuse to fuel pump relay for open circuit:

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
- Repair open circuit, if necessary
If the LED lights up:

- Check actuation.

Checking actuation

- Connect voltage tester VAG 1527 B to contacts 1 (positive) and 2 of
connector.
- Initiate output Diagnostic Test Mode (DTM) and actuate Wastegate
Bypass Regulator valve -N75-.
Output Diagnostic Test Mode

Display
Pa
ge 27 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2

-N75- waste
gate b
ypass re
gulator valve

LED must flash.
Pa
ge 28 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2

21-38
If the LED lamp does not flash or if it lights up
continuously:

- Connect VAG 1598/31 test box to wiring
harness leading to engine control module;
engine control module should not be connected:

Repair Manual, 1.8 Liter 4
-Cyl. 5V Turbo Fuel
Injection & Ignition, Engine Code(s): AWM, Repair Group 24


If the wiring is OK: - Check for open circuit and short to positive or Ground in following
wiring connection: Connector
Contact
Test box VAG 1598/31
2 104
- Repair any open/short circuit as necessary.
- Replace engine control module.
Pa
ge 29 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2

21-39


Charge Air Pressure sensor -G31-,
checking

Special tools and equipment

VAG 1526 A
VAG 1594 A
VAG 1598/31
VAS 5051 with VAS 5051/1
- or
VAG 1551 with VAG 1551/3 A
Pa
ge 30 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2