Operation CHARM: Car repair manuals for everyone.

General Information

The TCM directly controls the following:
- Transmission Control Relay
- Solenoid pack
- Torque management requests to the PCM

Additionally, the TCM broadcasts the following information over the communication bus for use by other vehicle control systems:
- Communication with the DRB Scan Tool for diagnostics
- Shift lever position to the BCM
- Shift lever position to the shift lever display
- Transmission oil temperature to the PCM in order to activate the cooling fans
- Vehicle speed - hard-wired to PCM and PCM sends to BCM over communication bus
- Limp-in status