Old Brake Light Switch Failures (Until ABS E4.2 Generation)
- Check pressure sensor installation ( correct installation in the system? Pressure line clogged or frozen up? ) - Check if the parameter setting matches with the ECU/System - Check wiring and the relating electric connectors of the pressure sensor ( Input short circuit to GND? Wires interruption? Sensor defect? ) - Check pressure sensor supply voltage ( voltage break down? ) - Check pressure sensor for a permanent zero pressure signal while the brake pedal is activated (several braking while driving from 0 to 50km/h). The braking pressure signal has to follow (show increase) the brake pedal activation. 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
current below normal or open circuit
Pressure Sensor Failure, open circuit or shorted to ground Pressure Sensor Failure, Permanent 0Bar Detection