Control Module

PURPOSE
The Transmission Control Module (TCM) controls and monitors the operation of the automatic transmission. The TCM records any faults it detects and will go into "Fail Safe Mode" to insure operation and safety of the transmission if a critical fault occurs.

OPERATION
The TCM collects information from various sensors and other control modules such as the M.P.I. Engine Control Module (ECM) for engine management information and the ABS Control Module for information about road speed. After evaluating this information, the TCM generates output signals to the actuators.

The TCM also generates output signals to the M.P.I. ECM (to retard ignition timing during upshifts and downshifts) and the A/C Control Head (to switch off the A/C compressor clutch under full throttle acceleration.)

The TCM monitors all inputs and outputs to detect any faults or values that are outside of normal operating range. It is equipped with a permanent fault memory and self-diagnosis capabilities.

If the Transmission Control Module detects a critical fault, or the TCM fails, the transmission will go into it's emergency running mode.