Relay, Fuel Pressure Shut-Off: Operation: Operation

WARNING: This page is about a different car, the 2015 RAM 3500 HD and 2015 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

The shut-off solenoid relay is used in place of the conventional fuel pump relay. It is used to electrically control operation of the high-pressure fuel shut-off solenoid. The solenoid is located within the fuel pressure regulator and the manual control valves on the cylinder tanks.

The Powertrain Control Module (PCM) operates the high-pressure fuel shut-off solenoid relay through a ground path.

The PCM turns the ground path off when the ignition switch is in the OFF position. When the ignition switch is in the ON or CRANK position, the PCM monitors the crankshaft position sensor and camshaft position sensor signals to determine engine speed and ignition timing (coil dwell). If the PCM does not receive the necessary crankshaft position sensor and camshaft position sensor signals when the ignition switch is in the Run position (indicating the engine has not started and is not running), it will de-energize the relay.