Auto Shutdown Relay

The Automatic Shutdown (ASD) relay is located in Power Distribution Center (PDC). See Figure . PDC is located in engine compartment. See Figure . The ASD sense circuit informs the Powertrain Control Module (PCM) when the ASD relay energizes. A 12-volt signal at this input indicates to the PCM that the ASD has been activated. This input is used only to sense that the ASD relay is energized. When energized, the ASD relay provides power to operate the injectors, ignition coil, generator field, O2 sensor heaters (both upstream and downstream), EGR solenoid and also provides a sense circuit to the PCM for diagnostic purposes. If the PCM does not receive 12 volts from this input after grounding the ASD relay, it sets a Diagnostic Trouble Code (DTC). The PCM energizes the ASD any time there is a crankshaft position sensor signal that exceeds a predetermined value. The ASD relay can also be energized after the engine has been turned off to perform an O2 sensor heater test.