Transmission Control Module (TCM)
TCM is located under instrument panel, to right of steering column. See Fig 1 . TCM determines shift points and torque converter lock-up timing based on input signals received from various components. Components consist of mode selector switch, throttle position sensor, transmission speed (RPM) sensor, gear position sensor, transmission oil temperature sensor, brake switch and kickdown switch.
TCM contains a self-diagnostic system which stores a Diagnostic Trouble Code (DTC). If a transmission problem exists, DTC(s) can be retrieved to determine transmission problem area.