Transmission Fluid Heater Coolant Control Valve

The transmission fluid heater coolant control valve is an electrically controlled solenoid to allow or block the flow of engine coolant. This electrically controllable valve is normally closed when not energized. The valve receives a fused 12V B+ supply when the ignition is in the run or start position and is grounded by the PCM via a low side driver. The PCM monitors the solenoid and circuits for electrical faults and sets an appropriate DTC.