0xD90E0D Trailer Control Modulator pressure sensor-Out Of Calibration
Action: Disconnect trailer. Set the ECU in After market mode via diagnosis. Release parking brake (SECURE VEHICLE). Disconnect connector on TCM side, measure voltage on the harness between sensor signal and sensor ground. If voltage is higher then 0.2V then repair wiring harness. If voltage is lower then connect TCM and measure pressure on yellow coupling head with all brakes released. If pressure is lower then (<0.1 bar) and the voltage on sensor signal is higher then 0.85V then replace TCM. If the pressure is higher then the 0.1 bar, then there is a pneumatic problem (TCM, parkbrake, FBM). Measure pressure on the parking brake input on the TCM (port 43), pressure should be higher than 6bar (KB to verify) all the time. If pressure is lower then check parking brake. Else check pressure on port 42 (backup) of TCM. If pressure is higher then 0.1 bar check footbrake module else replace TCM.
What you'll see
Symptom:
System reaction
SystemReaction: ESP control restricted. HSA off. Yellow EBS Warning Lamp.
Diagnostic depth
Detection: Measured voltage never comes into the offset range (0.5-0.85V).
Cause: Damaged wiring, pneumatic problem, pressure sensor in TCM, or central ECU (Means 0 bar pressure is never achieved, or percieved)