Faulty Signal

Faulty signal

Query

Question

Question

Does the car have a DSTC system?

Yes - DSTC

No - STC

------------------------

STC - Checking the connectors and cables

DSTC - DSTC

-------------------------------------------------

Checking the connectors and cables
Check the connectors for the relevant wheel sensor and the ABS control module for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the wiring and cable splices for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the connectors and wiring insulation for damage.
Check that the wheel sensor wiring is not too close to sources of interference such as electric motors, ignition cables, carphone wiring etc.
Remedy as necessary.

Other information:
- To disconnect the control module connector, see
- For the location of the wheel sensor connector, see Wheel sensors, rear, replacing Wheel Sensor Rear, Replacing
- To connect the breakout box, see Connecting the ABS breakout box Pinout Values and Diagnostic Parameters.

Was a fault detected?

Yes - Verification

No - Checking the wheel sensor and pulse wheel

-------------------------------------------------

Checking the wheel sensor and pulse wheel

- Remove the wheel for better access.
Check that the relevant wheel sensor is tightly against the shaft / hub. Check that there is no dirt between the sensor and mating surface.
Check that the relevant pulse wheel is correctly secured and free of damage, scratches etc.
Remedy as necessary.

Other information:
- To remove and replace the rear wheel sensors, see Wheel sensors, rear, replacing Wheel Sensor Rear, Replacing.

Was a fault detected?

Yes - Verification

No - Checking the brakes and wheel bearings

-------------------------------------------------

Checking the brakes and wheel bearings

Hint: A sticking brake or parking brake may have locked one or both wheels during driving. This will mean that the wheel sensor signal is not transmitted.

Check that the parking brake is not sticking or in contact with anything.
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.
Remedy as necessary.

Other information:
- To check and adjust the parking brake, see Replacing brake cables Service and Repair
- To check and replace the brake caliper, see Replacing the rear brake calipers, B5244T5, B5254T2 Replacing the Rear Brake Calipers
- To check and adjust the rear wheel bearings, see Rear wheel hub, replacing Rear Wheel Hub, Replacing.

Select Continue when the fault has been remedied.

Continue - Verification

-------------------------------------------------

Verification

Verification

Verification

Hint: After the repair it is necessary to check that the fault has been rectified.

- Ignition off.
- Connect the connectors, install the components, etc.
- Ignition on.
- Check that the ABS warning lamp comes on and goes out after approximately 2 seconds. If the lamp does not go out, the fault is still present.
- Test-drive the car as described in Test Drive Form (ABS), description Test Drive Form (ABS), Description.
Check the ABS warning lamp during the test-drive. If the warning lamp comes on, return to the workshop and read off the diagnostic trouble codes.

Does the lamp go out and stay out?

Yes - VERIFIED

No - VERIFICATION FAILED

------------------------

VERIFIED - Fault Found

VERIFICATION FAILED - Fault-tracing information

PAPER - No Fault Found

-------------------------------------------------

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 - FAULT-TRACING FAILED

No - Attempt New Test

------------------------

FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the connectors and cables

-------------------------------------------------

DSTC

Signal faulty

Checking connectors and wires
Check the connector of the ABS control unit and the relevant wheel sensor for contact resistance and oxidation, as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check cabling and joints for a short circuit to ground, as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check connectors and wiring insulation for damage.
Check that the wheel sensor wires are not in close proximity to sources of interference such as electric motors, ignition wires, mobile telephone leads etc.
Do the necessary corrective action.

Additional information:
- For disconnection of the control unit connector see Replacing the control module for ABS and dynamic stability and traction control (DSTC) Replacing the Control Module for ABS and Dynamic Stability and Traction Control (DSTC).
- For the location of the wheel sensor contact device see Wheel sensor, front, replacing Wheel Sensor Front, Replacing.
- To connect the test box, see Connecting the ABS/DSTC breakout box Pinout Values and Diagnostic Parameters.

Is there a fault?

Yes - Verification

No - Checking wheel sensor and sensor wheel

------------------------

Checking wheel sensor and sensor wheel

- Remove the wheel for better access.
Check that the relevant wheel sensor is fitted tight to the spindle/hub. There must not be any dirt between the sensor and contact surface.
Check that the relevant sensor wheel is properly tight and is free from damage, scratches etc.
Do the necessary corrective action.

Additional information:
- To remove/replace the rear wheel sensor, see Wheel sensor, front, replacing Wheel Sensor Front, Replacing.

Is there a fault?

Yes - Verification

No - Checking the brakes and wheel bearings

------------------------

Checking the brakes and wheel bearings

Hint: A sticking brake or the parking brake may have blocked one or both wheels during driving. This means that the wheel sensor signal has defaulted.

Check that the parking brake is not stuck or applied.
Check that the brake calliper is not stuck thus blocking the wheels.
Check that there is no play in the wheel bearing of the relevant wheel and that it is not stuck.
Do the necessary corrective action.

Additional information:
- To check/adjust the parking brake, see Replacing brake cables Service and Repair.
- To check/replace the brake calliper, see Replacing the rear brake calipers, B5244T5, B5254T2 Replacing the Rear Brake Calipers.
- To check/adjust the rear wheel bearings, see Rear wheel hub, replacing Rear Wheel Hub, Replacing.

Select Continue when the fault has been rectified.

Continue - Verification

------------------------

Verification

Verification

Verification

Hint: After the repair it is necessary to check that the fault has been rectified.

- Ignition off.
- Connect the connectors, install the components, etc.
- Ignition on.
- Check that the ABS warning lamp lights and goes out after approximately 2 seconds. If the lamp does not go out, the fault has not been rectified.
- Test-drive the car as described in Test driving Test Driving.
Check the ABS warning lamp during the test drive. If the warning lamp lights, return to the workshop and read the diagnostic trouble codes.