Description And Operation
DESCRIPTION
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.
The valve body includes the TCM, all solenoids and sensors, and can be referred to as the TCMA. The TCM is attached to the valve body between the transmission case and the valve body. If any component of the valve body including the TCM sensors or solenoids need replaced, the complete TCMA (valve body) must be replaced. For replacement of the TCMA (valve body). Refer to VALVE BODY, REMOVAL AND INSTALLATION .
OPERATION
| 1 - M6 Valve Body Bolt Hole |
| 8 - Solenoid C |
| 2- M5 Valve Body to Solenoid Body Bolt Hole |
| 9 - Torque Converter Clutch (TCC) Solenoid |
| 3 - Wiring Harness for Park Release Solenoid |
| 10 - Line Pressure Solenoid |
| 4 - Solenoid A |
| 11 - Park Release Solenoid |
| 5 - Solenoid D |
| 12 - High Impulse Solenoid (HIS) Wire Harness Connector |
| 6 - Solenoid B |
| 13 - Output Shaft Speed (OSS) Sensor |
| 7 - Solenoid E |
| 14 - Park Hold Solenoid |
| 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 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.
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 Antilock Brake System (ABS) module. Due to the complexity of the 8HP transmission control system, always refer to the transmission electrical/electronic diagnostics in this service information when attempting to diagnose transmission problems.