instrument cluster AUDI A4 1996 B5 / 1.G AWM Engine Additional Signals Checking Workshop Manual

24-164

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 Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

- 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

- Repair open circuit or short circuit if
necessary.
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24-165

Vehicle speed signal, checking


Notes:

The vehicle speed signal is generated by the
speedometer Vehicle Speed Sensor (VSS) -
G22- (at transmission) and is 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:

Repair Manual, Electrical Equipment, Repair
Group 90; Instrument cluster; Speed signal, checking


Test sequence

WARNING!

To reduce the risk of accident during road
tests, always observe safety precautions
Page 24
-1 .
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24-168
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

- Repair open circuit or short circuit if
necessary.
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24-175

Consumption signal for board
computer, checking


Note:
The consumption signal is transferred from the
Engine Control Module (ECM) to the instrument
cluster via CAN-bus. Check data exchange
between Engine Control Module (ECM) and
other CAN capable control modules Page 24
-
178

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24-176

Wire for fuel level signal, checking


Notes:

The signal helps with cause localization when
certain malfunctions are recognized (e.g.
combustion misfires).
The fuel level signal is transferred from the
instrument cluster to the Engine Control Module
(ECM) via CAN-bus. Check data exchange
between Engine Control Module (ECM) and
other CAN capable control modules Page 24
-178

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