Parking brake function - Plausibility Failure
â–¶ How to fix
Check pneumatics of vehicle/trailer for leakages and/or blockages. Replace TCM. Replace EPB if no pneumatic problem is found. (it may indicate piston, solenoid or sensor fault)
What you'll see
No driver-visible symptom recorded.
System reaction
Parking brake application may not be possible, proportional braking may not work properly, under braked trailer (jackknifing), trailer test function may not work. Yellow warning lamp.
Diagnostic depth
Detection
Pressure sensor or TCM pressure value changes too slow.
Possible cause
Sticking piston, faulty pressure sensor or TCM/trailer pneumatics error.