Wheel Speed Signal Absent

Fault symptoms
Speedometer or cruise-control system not working.

Conditions
- Open circuit or short-circuiting between pin 23 on the ABS control module and pin 10 on the MIU (K12).
- Open circuit or short-circuiting between pin 26 on the ABS control module and pin 63 on the Trionic control module.

Diagnostic help
The wheel-speed reading can be obtained from both the ABS control module and the control module receiving the signal.

See diagnosis in:
"Electrical system: MIU", refer to Instrument Panel, Gauges and Warning Indicators
Or
"Engine: Trionic" refer to Powertrain Management.

Diagnostic procedure
1. Checking Diagnostic Trouble Codes In The ABS
Any ABS Diagnostic Trouble Codes?

NO
Go To Step 2

YES
Go To Step 3

2. Checking The Wheel Speed Signal
^ Raise the car.
^ Unplug the control module connector in the relevant receiving system.





^ Turn the ignition switch to the ON position.
^ Connect the test lamp 86 11 857 to B+ (batt. positive) and the pin receiving the wheel speed.





^ Turn the wheel from which the system in question is receiving the vehicle speed signal





^ The test lamp should flash.

Is the function correct?

NO
Go To Step 4

YES
Go To Step 5

3. Checking Diagnostic Trouble Codes In The ABS
Continue fault diagnosis for the fault in question. C Code Charts

4. Rectifying The Lead
Check the lead between the ABS control module and the control module in question for short circuits, rectify if necessary.

When repair is complete
Go to Step 5

5. Final Check
^ Clear the diagnostic trouble codes in all systems.
^ Carry out a functionality test.

Is the function correct?

NO
Go To Step 6

YES
Go To Step 7

6. Final Check
The steps taken to correct the fault were correct.
^ Diagnosis is complete.

7. Final Check
See Before changing a control module, refer to General Fault Diagnosis.
^ Diagnosis for this fault code is complete.