Faulty Signal
Faulty signal
Checking the wheel sensor and pulse wheel
- Ignition off
- Remove the wheel for better access.
Check that the relevant wheel sensor is mounted tightly against the shaft or hub. Check that there is no dirt between the sensor and mating surface.
Check that the magnetic pulse wheel is correctly secured and free of damage, scratches (for example scratches, deformation).
Remedy as necessary.
Other information
- Transmission input speed sensor rear wheels Transmission Input Speed Sensor Rear Wheels
- Transmission input speed sensor, front wheels Transmission Input Speed Sensor, Front Wheels
Was a fault detected?
Yes - Verification
No - Checking the brakes and wheel bearings
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Checking the brakes and wheel bearings
Hint: A sticking brake can block one or both wheels when the car is being driven. This will mean that the wheel sensor signal is not transmitted.
Check that the brake calipers are not sticking and locking the wheels.
Check the wheel bearing on the relevant wheel for play. Check that the wheel rotates freely and is not sticking. If the wheel has too much play, especially check the mounting of the hub on the spindle.
Remedy as necessary.
Other information
- Front brake caliper, B5254T7, AW55-50/51SN, B5254T7, M66 Front Brake Caliper Brake pads, front, B5254T7, AW55-50/51SN, B5254T7, M66 Brake Pads, Front Front brake disc, B5254T7, AW55-50/51SN, B5254T7, M66 Brake Disc Front, Replacing
- Rear brake caliper Rear Brake Caliper
- Wheel bearings and wheel hubs, front Wheel Bearings and Wheel Hubs, Front
- Rear wheel hub, AW55-50/51SN, M56, MMT6, M66 Rear Wheel Hub
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, connectors, etc.
- Ignition on
- Test drive the car according to: Test Drive Form (DSTC (dynamic stability and traction control) /brake control module), description Test Drive Form (DSTC (Dynamic Stability and Traction Control) /Brake Control Module), Description
Check the ABS warning lamp during the test drive.
If the fault has been remedied the lamp will go out when the speed exceeds 20 km/h.
If the warning lamp does not go out, return to the workshop and read off the diagnostic trouble codes (DTCs).
Does the ABS warning lamp go out and remain unlit?
Yes - Troubleshooting procedure complete
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 wheel sensor and pulse wheel
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