Module, Transmission Control (TCM): Operation
The Transmission Control Module (TCM), or Transmission Control Module Assembly (TCMA) is extremely sensitive to Electrostatic Discharge (ESD). Always use a ground strap and follow the ESD guidelines in ELECTROSTATIC DISCHARGE SENSITIVE DEVICES. Failure to follow these instructions may result in damage to the TCM/TCMA.
| 1 - Solenoid A |
| 6 - Torque Converter Clutch (TCC) Solenoid |
| 2- Solenoid D |
| 7 - Line Pressure Solenoid |
| 3 - Solenoid B |
| 8 - Park Release Solenoid |
| 4 - Solenoid E |
| 9 - Park Hold Mechanical Solenoid |
| 5 - Solenoid C |
| 10 - Park Release Mechanical Valve |
| 1 - Input Speed Sensor (ISS) |
| 4 - Output Speed Sensor (OSS) |
| 2 - Transmission Control Module (TCM) (Includes Transmission Temperature Sensor) |
| 5 - Park Position Sensor |
| 3 - External Wire Harness Connector |
The valve body, which includes the TCM, controls the delivery and pressure of transmission fluid. The TCM is integrated into the valve body. The TCM regulates the amount of hydraulic pressure used to engage the clutches and the TCC, in addition to directing hydraulic pressure to engage or release any given clutch for any given required gear. The TCM will actuate the valves via solenoids based on the position of the shifter, transmission fluid temperature, engine operating conditions, traction conditions and driver demands. During a shift, the TCM will actuate the solenoids to match the gear ranges to the optimal torque range of the engine based on the position of the accelerator pedal, shifter and vehicle speed as determined by the Powertrain Control Module (PCM) based on input from the Vehicle Speed Sensor (VSS) and the Antilock Brake System (ABS) module.
If the TCMA is replaced, it must be programmed and a drive learn needs to be performed before returning the vehicle to the customer for programming and drive learn procedures. Refer to MODULE PROGRAMMING.