Theory Of Operation

The Transmission Control Module (TCM) performs several diagnostic checks to determine whether the temperature of a clutch is above a calibrated temperature value. These diagnostic checks use temperature models which are based upon input speed and output speed, current gear, target gear, calculated effective pressure on engaging clutch and on the disengaging clutch. The Diagnostic Trouble Codes (DTCs) set by these diagnostics are used to protect the durability of the clutches by controlling the shift operation. This fault is can be used to initiate a calibration strategy and for diagnostic information in case other faults are set.