Transaxle Control Unit (TCU)

The TCU receives information from various input devices and controls various output devices for different gear operation. The TCU is located behind the instrument panel, near center of console, and contains a 42-pin connector. See Fig 1 , Fig 2 or Fig 3 . On all models except Colt Vista and Summit Wagon, a POWER/ECONOMY switch, located on center of console, is used to change shift patterns. The pre-set shift patterns are controlled by the TCU. The TCU controller contains a self-diagnostic system which stores a fault code if a transaxle fault exists. Fault codes can be retrieved to determine transaxle problem areas. See SELF DIAGNOSTIC SYSTEM  . The TCU contains a fail-safe mode. If certain fault codes are set, transaxle will enter the fail-safe mode. When in fail-safe mode, transaxle will remain in 2nd or 3rd gear with no upshifts or downshifts. Transaxle will also function in Park, Neutral and Reverse when in fail-safe mode. Transaxle controller works in conjunction with the engine controller for receiving information for transaxle control. See ENGINE CONTROLLER LOCATION  table.