Faulty Transmission Control Module (TCM)
Transmission Control Module (TCM) harness is open or shorted
Transmission Control Module (TCM) circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
This diagnostic checks for the electrical faults of the power supply to the Transmission Control Module (TCM). The supply is provided to TCM via three different input pins named PWRSPLYVS1, PWRSPLYVS2 and PWRSPLYVS3. The diagnostic detects if each power supply input is shorted to ground or has an open circuit fault by continuously measuring its voltage value. When each of the voltage values is less than its threshold, then that diagnostic will set a fault in the TCM.