Coolant Valve

WARNING: This page is about a different car, the 2006 Land Rover Range Rover. However, it is still accessible from the selected car via links, so may be relevant.

The coolant valve controls the coolant flow to the heater core. A single coolant valve controls the coolant flow to both sides of the heater core on manual systems. On automatic systems, separate coolant valves control the coolant flow to each side of the heater core. The coolant valves are installed in the engine compartment on a bracket attached to the side of the left-hand (LH) suspension turret.

Each coolant valve is a normally open solenoid valve controlled by a pulse width modulation (PWM) signal from the ATC module. The ATC module changes the length of time the coolant valve is open each duty cycle between 0 second (valve closed) and 3.6 seconds (valve held open). On the automatic system, the PWM (pulse width modulated) signals to the two valves are phase offset by 1.8 seconds to reduce coolant flow fluctuations.