check engine AUDI A4 1996 B5 / 1.G APB Engine Charge Air System With Turbocharger Workshop Manual

21-16

- Select measuring value block 117.

- Check function of accelerator pedal in display
field 2 by briefly depressing pedal to Wide Open
Throttle.

Display fields

1 2 3 4
Display group 117: Charge air pressure regulation
Display 1 RPM
% % mbar
Indicated Engine speed (RPM)
Accelerator pedal
position Throttle valve angle Specified charge air
pressure
Specified value
0...100
Note: If the specified value 100% is not reached at
Wide Open Throttle (WOT):

- Check accelerator pedal.

- Select measuring value block 116.
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21-17

- Check correction factors in display fields 2 to
4.

Display fields

1 2 3 4
Display group 116: Charge air pressure regulation
Display 1 RPM
% % mbar
Indicated Engine speed (RPM)
Correction factor
Fuel Correction factor
Coolant temp. Correction factor
Intake air temp.
Specified value


Note: If display field 2 indicates a correction factor <0
%, fuel quality is probably incorrect.

- Fill tank with prescribed fuel quality.
If display field 3 indicates a correction factor <0
%, coolant temperature is too high (heat warning
lamp lit in instrument cluster) or the Engine
Control Module is receiving an incorrect
temperature signal from the instrument cluster.

- Check coolant temperature display.

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21-20

Note:
The recirculating valve for turbocharger -N249
and wire connections are monitored by the
Engine Control Module (ECM).

- Connect VAS 5051 tester or VAG 1551 scan
tool and select control module for engine
electronics using "address word" 01. Engine
must run at idle for this.

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 01


- Check DTC memory of Engine Control Module
(ECM).

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 01

If a Diagnostic Trouble Code (DTC) relating to
the recirculating valve for turbocharger -N249- is
displayed:

-
Disconnect hoses from valve; harness connector
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21-21

- Initiate output Diagnostic Test Mode (DTM) and
activate recirculating valve for turbocharger -
N249-.

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 01

Output diagnostic test mode Recr. valve for turbocharger -N249

Indicated on display
If valve does not click:
If valve does not open and close properly: Valve must click...
...and must open and close (can be tested by blowing into assisting
hose).
- Check internal resistance of valve.
- Replace recirculating valve for turbocharger -N249-.
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21-23

Checking voltage supply

Note:
Voltage is supplied to the recirculation valve via
the Fuel Pump (FP) relay.

Test requirement:

Fuse for recirculation valve OK

- Disconnect connector at valve.

- Connect VAG1527B voltage tester as follows:Harness connector terminal
Measure to
1 Engine Ground (GND)
- Operate starter briefly.

LED must light.
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21-24
If LED does not light:

- Check wire connection from terminal 1 to Fuel
Pump (FP) relay via fuse for open circuit.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations
- Repair open circuit if necessary.
If wire connection is OK:

- Check Fuel Pump (FP) relay.

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 24

If LED lights:

- Check activation, Page 21
-25
.
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21-25

Checking activation

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel Injection & Ignition,
Engine Code(s): APB, Repair Group 01

If LED does not blink or if it remains constantly lit:
Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel Injection & Ignition,
Engine Code(s): APB, Repair Group 24
- Connect VAG 1527B voltage tester to connector terminals 1 (B+) and
2.
- Initiate output Diagnostic Test Mode (DTM) and activate recirculating
valve for turbocharger -N249-.

LED must blink.
- Connect VAG 1598/31 test box at wiring harness to ECM. Do not
connect ECM.

- Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+: Harness connector terminal
VAG 1598/31 test box
Bushing
2 9
- Repair open circuit or short circuit if necessary.
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21-28

Note:
The charge air pressure sensor -G31- and wire
connections are monitored by the Engine Control
Module (ECM).

- Connect VAS 5051 tester or VAG 1551 scan
tool and select control module for engine
electronics using "address word" 01. Engine
must run at idle.

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 01


- Check DTC memory of Engine Control Module
(ECM).

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 01

If a Diagnostic Trouble Code (DTC) relating to
the charge air pressure sensor -G31- is
indicated:
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21-29

Checking voltage supply

- Switch ignition off.

- Remove engine cover (arrows).
- Disconnect connector at charge air pressure sensor.

If specified value is not obtained: - Connect multimeter between terminal 1 and 3 of harness connector for
voltage measurement.
- Switch ignition on.

Specification: about 5 V
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21-30

- Connect VAG 1598/31 test box to wiring
harness for Engine Control Module (ECM), also
connect ECM -1-.

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 24


If the specified value is met: - Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+: Harness connector terminal
VAG 1598/31 or test box
Bushing
1 108
3 98
- Repair open circuit or short circuit if necessary.
- Check signal wire, Page 21
-31
.
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