Signal Missing

Signal missing

Checking the connectors for the control module and wheel sensor








- Ignition off
- Check the wheel sensor and control module connectors. Check for contact resistance and oxidation
- Reinstall the components, reconnect the connectors etc.
- Raise the car so that the relevant wheel is clear of the ground
- Ignition on
- Read off the wheel speed for the relevant wheel.
Spin the relevant wheel and check that the wheel speed is updated.
If the wheel speed is updated, the cause of the fault was loose connections in the connectors for the control module or wheel sensor.

Note! The speed signal will only be active for approximately 20 seconds. Activate the function again if necessary.

Other information
- To disconnect the wheel sensor connector, see Wheel sensor front, replacing Wheel Sensor, Front, Replacing
- To disconnect the connector for the brake control module (BCM), see Connecting the breakout box, brake control module (BCM) Connecting the Breakout Box
- Checking wiring and terminals Checking Wiring And Terminals





Is the wheel speed updated?

Yes - FAULT FOUND

No - Checking wiring and sensors

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Checking wiring and sensors








Checking the power supply
Check the signal cable between control module
- terminal #45 (#A45) (left front)
- #34 (#A34) (right front).
and terminal #1 on the relevant sensor. Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.
Checking the signal cable
Check the signal cable between control module
- terminal #46 (#A46) (left front)
- #33 (#A33) (right front).
and terminal #2 on the relevant sensor. Check for an open-circuit. Check for a short-circuit to ground. Check for a short-circuit to supply voltage.
Checking the function of the sensor
Check the sensor. Ensure that the breakout box is connected, the sensor is connected and the ignition is on. Measure the signal from the sensor. Connect a voltmeter between:
- terminals #45 (#A45) and #46 (#A46) (left front)
- terminals #34 (#A34) and #33 (#A33) (right front).
on the breakout box. The voltage should vary by approximately 1 V when the pulse wheel is rotating. Replace the wheel sensor if the voltage is faulty.

Hint: Particularly check the wiring at the steering shaft.

Remedy as necessary.

Other information:
- To connect the breakout box, see Connecting the breakout box, brake control module (BCM) Connecting the Breakout Box
- To replace the wheel sensor, see Wheel sensor front, replacing Wheel Sensor, Front, Replacing
- For information about signals, Signal Specification, Brake Control Module (BCM) with DSTC (Dynamic Stability and Traction Control) and Signal Specification, Brake Control Module (BCM) with STC/ TRACS
- Checking wiring and terminals Checking Wiring And Terminals









Continue - Verification

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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off
- Reinstall the components, reconnect the connectors etc.
- Raise the car so that the relevant wheel is clear of the ground
- Ignition on
- Read off the wheel speed for the relevant wheel.
Spin the relevant wheel and check that the wheel speed is updated.

Note! The speed signal will only be active for approximately 20 seconds. Activate the function again if necessary.





Is the wheel speed updated?

Yes - Verification completed

No - Fault-tracing information

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Fault-tracing information




Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - Exit Fault-Tracing

No - Attempt New Test

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Attempt New Test - Checking the connectors for the control module and wheel sensor

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