1997 AUDI A4 AWM Engine Charge Pressure Leak Test Workshop Manual

21-28


- Connect auxiliary hose to valve connector marked with an arrow.
- Initiate output Diagnostic Test Mode (DTM) and activate recirculating
valve for turbocharger -N249-.
Output Diagnostic Test Mode Recircul. valve for turbochar
ger -N249-

Display:
If the injector does not click:
If valve does not open or close properly:
The valve should click ... ... and must open and close (check by blowing into the auxiliary
hose).
- Check internal resistance of valve.
- Replace recirculation valve for turbocharger -N249-.
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21-29

Checking internal resistance

- Disconnect connector from recirculation valve for turbocharger -N249-
(-1-).

If specified value is not attained:
If specified value is attained: - Connect multimeter to injector to measure resistance.
Specified value: 27 to 30
- Replace recirculating valve for turbocharger -N249-.
- Check power supply.
Pa
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21-30

Checking power supply

Note:
The power supply for the recirculating valve is via
the fuel pump relay.

Test requirements:

Fuse for recirculating 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


- Disconnect wiring connector from valve.

- Connect voltage tester VAG 1527 B as follows:Connector
Measure to
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contact
1 Engine Ground
- Operate starter briefly.
The LED must light up.
Pa
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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
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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
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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
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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
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