Transmission Control Module (TCM) Monitoring Functions

The TCM monitors all transmission input and output to identify possible transmission failures. If a fault is detected, the TCM takes the appropriate action to make sure that the transmission enters a safe mode of operation.

• Voltage Supply - this function monitors the vehicle battery voltage.
• Watchdog Monitoring - the watchdog monitoring has 2 functions:
  • Checks for faults in the driver circuits by activating each driver.
  • Checks to see if the safety circuit is functioning correctly.
• TCM Temperature - If the TCM temperature rises above a predetermined temperature, the TCM will shut down. Prior to shutting down, the TCM will log a fault code during shutdown. The transmission will enter a mechanical limp-home mode.
• Pressure Regulator/Solenoid - Each pressure regulator and solenoid is monitored for open and short circuits. The TCM also checks that the current being delivered to each solenoid valve or pressure regulator is within limits.
• Torque Converter Control - The TCM checks and verifies that the torque converter has been engaged correctly. If the torque converter has not engaged correctly, the TCM will carry out the fail-safe action of opening the converter clutch.