Automatic Shutdown Relay

Automatic Shutdown (ASD) relay is located in Power Distribution Center (PDC) near the battery or next to radiator coolant recovery bottle. For ASD relay location within PDC, refer to PDC cover label.

ASD relay supplies battery voltage to fuel injectors, generator field winding, and ignition coil. The relay contacts are normally open.

Power is supplied to relay coil when the ignition switch is turned on. The PCM controls the ground circuit, which energizes the relay coil and closes the relay contacts.

The PCM will only ground the relay when ignition switch is in the Run or Start positions, and activity is sensed through the crankshaft position sensor and the camshaft position sensor in the distributor. If the PCM senses the RPM signal has stopped, it will remove the ground from relay coil, which will cause the contacts to open and remove power from the circuit.