DTC P090: TCC Brake Switch Input Circuit Problem: Description

This diagnostic test functions on the assumption that a sudden decrease in non-drive (rear) wheel speed must be caused by a brake application. Non-drive wheel speed and stop lamp switch status supplied to the PCM through serial data from the Electronic Brake and Traction Control Module (EBTCM).

If there is a 2.5 MPH or greater decrease of non-drive wheel speed in 0.2 second and a transition of the extended travel brake contacts of the torque management brake switch or stop lamp brake switch without a transition of the TCC switch contacts of the torque management brake switch the counter is incremented. When the counter reaches 5, Code P090 is set. The counter will be reset to zero if a transition of the TCC contacts of the torque management brake switch is noticed before the counter reaches 5.