wiring AUDI A4 1998 B5 / 1.G ATQ Engine Additional Signals Testing User Guide

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If specified value is obtained:

Checking voltage supply

If LED does not light up:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
1 Chassis Ground (GND)
- Switch ignition on.

LED must light up.
- Check wire connection from terminal 1 of connector to fuse for open
circuit and short circuit to Ground (GND):
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If LED lights up:

Checking activation

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

- Check the following wire connection for open circuit and short circuit to
Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
2 39
- Repair open circuit or short circuit if necessary.
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Wire for crash signal, checking

The Engine Control Module (ECM) receives the
crash signal ("Crash shut-off was triggered") from
the airbag control module.
When the airbag control module sends the crash
signal to the ECM (during an accident or when
output DTM is being performed for the airbag
system), the ECM switches the Fuel Pump (FP)
off. This means that the engine will stop running
but can be started again afterward (e.g. to
remove vehicle from danger).

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17


- Check the following wire connection for open
circuit and short circuit to Ground (GND) and B+:

Test box
VAG1598/31
Socket
Control module for
Airbag -J234-
Terminal
67 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations binder
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- Repair open circuit or short circuit if
necessary.

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder If no malfunctions are found in wire:

- Check DTC memory of control module for
airbag:

Repair Manual, Body
-On Board Diagnostic
(OBD), Repair Group 01; On Board Diagnostic (OBD) of airbag system BAE (basic trigger unit) with side airbag; DTC memory, checking

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Test requirement:

Control module coding OK Page 01
-71
.

Test sequence

- Switch ignition off.

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

- Check the following wire connection for open
circuit and short circuit to Ground (GND) and B+:

Test box
VAG1598/31
Socket
ABS control module (w/EDL)
-J104-
Terminal
74 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations binder
If no malfunctions are found in wire:

- Replace ABS control module.
If the malfunction is indicated again after
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Example 1:

From the DTCs stored in the memories, you have determined that control
module 1 is not communicating with control modules 2 and 3.
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder Control module
DTCs stored in DTC memories:
1
Missing signal from control module 2Missing signal from control module 3
2 Missing signal from control module 1
3 Missing signal from control module 1
- Switch ignition off.
- Disconnect the control modules connected across the bus wires and
check the bus wires for an open circuit. - Replace control module 1 if no malfunctions can be found in the bus
wires.
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Example 2:

From the DTCs stored in the memories, you have determined that control
module 2 is not communicating with control modules 1 and 3.
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder Control module
DTCs stored in DTC memories:
1
Missing signal from control module 2
2 Missing signal from control module 1Missing signal from control module 3
3 Missing signal from control module 2
- Switch ignition off.
- Disconnect the control modules connected across the bus wires and
check the bus wires for an open circuit. - Replace control module 2 if no malfunctions can be found in the bus
wires.
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Example 3:
Using the DTCs stored in the memories, you
have determined that none of the control
modules are sending or receiving signals.

Control
module
DTCs stored in DTC
memories:
1
Powertrain databus faulty
2 Powertrain databus faulty
3 Powertrain databus faulty

- Switch ignition off.

Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Disconnect the control modules connected across the bus wires and
check bus wires for a short circuit to B+ and Ground (GND).
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