ASD Relay Control Circuit

PURPOSE
The Automatic Shutdown Relay (ASD) controls the 12-volt source to the fuel injectors, ignition coil, EGR solenoid and the generator.

The relay is located in the power distribution center (PDC).

OPERATION
One side of the relay control coil is supplied with 12 volts when the ignition switch is turned to the "RUN" position. The circuit is completed when the other side of the relay coil is grounded by the powertrain control module (PCM).
- The PCM grounds the relay when the ignition switch is in either the RUN or CRANK position and engine RPM is detected.
- If engine RPM is not detected, the PCM will remove the ASD relay control circuit ground.

NAME OF CODE:
Auto Shutdown Relay Control Circuit

WHEN MONITORED:
With the ignition key ON and battery voltage greater than 10 volts.

SET CONDITION:
An open or shorted condition is detected in the auto shutdown relay control circuit.

POSSIBLE CAUSES:
- Relay coil open or shorted
- Fused ignition switch output circuit open
- ASD relay control circuit open or shorted
- Inoperative circuit driver in PCM