Old Brake Light Switch Failures (Until ABS E4.2 Generation)
- Check wiring and the relating electric connectors of the pressure sensor ( Input short circuit to UB? ) - Check pressure sensor for a permanent braking signal while the brake pedal is not activated. The braking signal has to be at 0Bar (0psi) or correspond to the non-braking voltage level in the sensor specification. Remark: A repair can be considered successful only when the vehicle is driven again in order to detect possible dynamic failure.
What you'll see
No driver-visible symptom recorded.
System reaction
ESC/RSC disabled Hillhold Function disabled EBL switches to EBD mode if exceeding 2,5 m/s2 and HSA is deactivated
Diagnostic depth
voltage above normal or shorted high
Pressure Sensor Failure, shorted to UBATT Pressure Sensor Failure, Permanent Pressure Signal Detection