Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information

Condition
The brake control module (BCM) receives information about wheel speed from the wheel sensors. The wheel sensors, which are on the wheel mounting, read off a pulse wheel on the wheel spindle. The wheel sensors are supplied with 12 V. When the magnetic wheel rotates, the sensor produces a pulsed current of 7 or 14 mA (quadratic wave). The amperage depends on the position of the damaged wheel.
The diagnostic trouble code (DTC) is stored if the control module detects that:
- The difference in speed between the wheel with the lowest speed and the wheel with the highest speed is too large.
- The difference in speed between the wheel with lowest and that with second lowest speed is unreasonable.
- The appearance of the signals from each wheel sensor have implausible rises in the signal value.
- The pressure reduction on each wheel during ABS control is incorrect.
The control module's test for the diagnostic trouble code (DTC) starts in the event of:
- Speeds above 20 km/h.
- More than one ABS control.

Note! The control module can only detect the fault once the test has been started and the diagnostic trouble code (DTC) is stored when the conditions are met.





Substitute value
- ABS blocked.
- Traction control (TC) blocked.
- Stability control (SC) blocked.
- Active yaw control (AYC) is blocked.
- Electronic brake force distribution (EBD) blocked.
- Brake assistance (BA) blocked.

Hint: Brake system, abbreviations Brake System, Abbreviations

Possible source
- Dirt or metal particles between sensor ring gear and wheel sensor.
- One of the wheels has been blocked while the car has being driven.
- Loose wheel sensor.
- Gap between wheel sensor and pulse wheel too large or too small.
- Hub vibration or play in the wheel bearings.
- Damaged pulse wheel.
- Damaged wheel sensor.

Note! This diagnostic trouble code (DTC) is not due to an internal hardware fault in the Brake control module (BCM) and must not be remedied by replacing the control module.

Fault symptom[s]

- ABS warning light on
- Brake circuit warning light on
- Anti-spin warning lamp lit
- ABS function is not working
- Traction control not working
- Stability function is not working
- Adaptive cruise control; No Functionality
- Collision avoidance driver support; No Functionality
- Front monitoring/Active safety/City Safety does not work