diagram AUDI A4 2001 B5 / 1.G 01V Transmission Torque Tube Remove And Install Workshop Manual

01-265

Two-wire bus system, checking


If the DTC table indicates to check the bus:

- Use the applicable wiring diagram, determine
how many control modules communicate with
each other via the bus.

- Press the -0- button twice to select the function
"Automatic test sequence".

- Before checking the bus wires, make sure that
none of the control modules connected are
malfunctioning.

A malfunction will disrupt communication to
other control modules.

Is there a malfunction?

- Fix the malfunction before proceeding.

- Note malfunction and erase DTC memory of all
control modules Checking and erasing DTC
memory of the relevant control module.
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01-267

Two control modules communicate via a
"two-line bus system"

- Switch ignition off.

Electrical Wiring Diagrams, Troubleshooting & Component Locations - Disconnect both control modules.
- Check bus wires for open circuit.

Electrical Wiring Diagrams, Troubleshooting & Component Locations - Check whether there is a short circuit between bus wires.
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01-269

Three or more control modules are
communicating across a "two-line bus
system"

- Analyze DTCs stored in the memories of the
control modules.

Example 1:
From the DTCs stored in the memories, determined that control module 1
is not communicating with control modules 2 and 3.
Electrical Wiring Diagrams, Troubleshooting & Component Locations 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 bus wires for open circuit. - Replace control module 1 if bus wires are OK.
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bus, function
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01-270


Example 2:
From the DTCs stored in the memories, determined that control module 2
is not communicating with control modules 1 and 3.
Electrical Wiring Diagrams, Troubleshooting & Component Locations 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 bus wires for open circuit. - Replace control module 2 if bus wires are OK.
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bus, function
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01-271

Example 3:
Using DTCs stored in the memories, determined
that none of the control modules are sending or
receiving signals.

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

- Switch ignition off.

Electrical Wiring Diagrams, Troubleshooting & Component Locations - Disconnect the control modules connected across the bus wires and
check for a short circuit between the bus wires.

- Check bus wires for short circuit to B+ or Ground (GND).
Pa
ge 9 of 10 CAN-
bus, function
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.AT02.01.15