BCM-0021

BCM-0021 Right Front Wheel Sensor, Faulty Signal
Condition





For Diagnostic Trouble Codes (DTCs) BCM-0011 (left front wheel sensor) and BCM-0021 (right front wheel sensor), the Brake Control Module (BCM) is able to register faults in three different ways:
1. 1Diagnostic Trouble Code (DTC) BCM-0011 or BCM-0021 is stored, depending on the wheel sensor, when the control module receives a signal from the wheel sensor indicating that the wheel has stopped or is rotating too slowly in relation to the reference speed of the car when driving or during ABS control when the speed is above 20 km/h.
2. The control module has a counter (extrapolation counter) which counts the number of times that changes in wheel speed are greater than the permitted value (calculated). Diagnostic Trouble Code (DTC) BCM-0011 or BCM-0021 is stored, depending on the wheel sensor, if the wheel acceleration is greater than in the other wheel sensors
3. Diagnostic Trouble Code (DTC) BCM-0011 or BCM-0021 is stored (depending on the wheel sensor) if the control module registers that the signal from the wheel sensor is missing when starting from a speed below 6 km/h or if the slowest wheel rotates at a speed less than 40-60 % (depending on vehicle speed) of the fastest wheel and no open-circuit is detected in the wheel sensor circuit.

The Diagnostic Trouble Code (DTC) can be diagnosed at speeds above 10 km/h.

Substitute value
- The ABS is blocked
- Electronic Brake Force Distribution (EBD) is blocked if two or more wheel sensors are not working
- Traction control is blocked
- Stability control is blocked
- Active yaw control is blocked
- Brake assistance is blocked.

Hint: For information about brake system abbreviations, Refer to Description and Operation.

Possible source
- One of the wheels has been blocked while the car has being driven
- Loose wheel sensor
- The gap between the wheel sensor and the pulse wheel is too large or too small
- Hub vibrations or play in the wheel bearings
- Defective pulse wheel
- Defective wheel sensor.

Fault symptom[s]
- General warning lamp lit
- The ABS warning lamp is lit
- The anti-spin warning lamp is lit (up to and including 2002 model year)
- The ABS system does not function
- Anti-spin does not function
- The stability control system does not function
- The traction control system does not function.