Low transmission fluid level
Dirty transmission fluid
Faulty Torque Converter Clutch Solenoid
Torque Converter Clutch Solenoid harness is open or shorted
Torque Converter Clutch Solenoid circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
Transmission will not shift gears.
The torque converter clutch solenoid valve switches the hydraulic circuit to engage/disengage the torque converter clutch. When the torque converter clutch solenoid valve is turned ON, hydraulic pressure is applied to the torque converter clutch. When the torque converter clutch solenoid valve is turned OFF, hydraulic pressure to the torque converter clutch is interrupted.
The powertrain control module (PCM) controls the torque converter clutch solenoid valve. The driver circuit has a diagnostic function that detects and outputs the state of a short or open circuit, and sends a return signal to the PCM. If the return signal during the PCMs command is not appropriate, the PCM detects a malfunction and stores a DTC.