Relay, Auto Shut Down: Operation

The ground circuit for the coil within the Automatic Shutdown (ASD) relay is controlled by the Powertrain Control Module (PCM). The PCM operates the ASD relay by switching its ground circuit on and off.

The ASD relay powers a number of critical circuits through the Power Distribution Center (PDC). These circuits include:

• Four ASD feed circuits to the PCM
• Fuel injectors
• Ignition coils
• Upstream Oxygen (O2) sensor heater
• Downstream O2 sensor heater
• Evaporative (EVAP) purge control solenoid

One of the ASD feed circuits is used as an ASD sense so that the PCM can determine if the ASD circuit is powered or not.