instrument cluster AUDI A6 1996 C5 / 2.G ATQ Engine Additional Signals Testing Workshop Manual

24-166

Engine speed signal, checking


Note:
The engine speed signal is output at terminal 37
of the Engine Control Module (ECM). The signal
is used, among other things, for RPM display in
the instrument cluster.

- 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
Instrument cluster

Terminal
37 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations binder

- Repair open circuit or short circuit if
necessary.
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gnals, testin
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p://127.0.0.1:8080/audi/servlet/Dis
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pair&id=AUDI.B5.FU05.24.6

24-168

Vehicle speed signal, checking


Notes:

The vehicle speed signal is generated by the
Vehicle Speed Sensor (VSS) -G68- (at
transmission) and processed in the instrument
cluster.
The processed signal enters at terminal 54 of
the ECM and is used for idle stabilization and
tip-in shock reduction during shifting.

Test requirement:
Function and display of speedometer OK.
Troubleshooting:

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
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p://127.0.0.1:8080/audi/servlet/Dis
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pair&id=AUDI.B5.FU05.24.6

24-170

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

- Connect VAG1527B voltage tester to sockets 3
(B+) and 54 (VSS) of VAG1598/31 test box.

- Switch ignition on and turn front left wheel by
hand.


LED must blink (very brief blink signal).
If LED does not blink:

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

Test box
VAG1598/31
Socket
Instrument cluster

Terminal
54 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations binder

- Repair open circuit or short circuit if
necessary.
Pa
ge 6 of 44 Additional si
gnals, testin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.6

24-171

Wire for fuel level signal, checking


Notes:

The Engine Control Module (ECM) receives the
fuel level signal from the instrument cluster.
The processed signal enters at terminal 30 of
the ECM and is used to determine the cause of
certain recognized malfunctions (e.g.
combustion misfires).

- 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
Instrument cluster

Terminal
30 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations binder

- Repair open circuit or short circuit if
necessary.
Pa
ge 7 of 44 Additional si
gnals, testin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.6