Torque Converter Clutch (TCC) Lock-Up

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1995 Jeep Grand Cherokee, 1995 Dodge Ram Wagon, 1995 Dodge Ram Van, 1995 Dodge Pickup, and 1995 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.

Torque converter clutch lock-up is activated only in Drive and is controlled by Powertrain Control Module (PCM). PCM is located on passenger side of firewall on all models except AN body. On AN body, PCM is located on passenger inner fender. The TCC solenoid, located on the valve body, receives battery voltage when ignition is turned on. The TCC solenoid and overdrive solenoid share a 3-wire electrical connector at the transmission.

NOTE: The TCC solenoid may be referred to as the lock-up solenoid, lock/unlock solenoid or Electronic Modulated Converter Clutch (EMCC) solenoid.

The PCM controls the TCC solenoid ground circuit for torque converter clutch lock-up operation when transmission is in overdrive or 4th gear. The valve body lock-up timing valve releases torque converter clutch lock-up before the 4-3 downshift occurs. Torque converter clutch lock-up depends on input signals to the PCM provided by various sensors.

On Pickup applications with 5.9L Diesel engine and gasoline models with special auxiliary transmission oil cooler, torque converter clutch lock-up is controlled by the PCM and the transmission fluid temperature sensor. Transmission fluid temperature sensor is located in oil cooler outlet line, near the transmission case. Transmission fluid temperature sensor monitors transmission fluid temperature and is in the circuit with the TCC solenoid on the valve body and the PCM.

NOTE: CNG powered vehicles are not equipped with transmission temperature sensor.

Transmission fluid temperature sensor prevents TCC lock-up operation when transmission fluid temperature is less than 70°F (21°C). Transmission fluid temperature sensor will either downshift transmission to 3rd gear or prevent a 3-4 upshift when transmission fluid temperature exceeds 270-275°F (132-135°C).

TCC lock-up is monitored by the PCM. The PCM self-diagnostic system stores a diagnostic fault message in the memory in event of a malfunction. Diagnostic fault message can be retrieved for TCC lock-up diagnosis. See SELF-DIAGNOSTIC SYSTEM .