Auto Shutdown (ASD) Relay

NOTE: If ASD relay is suspected of causing a fuel or ignition system malfunction, use Diagnostic Readout Box (DRB) to diagnose ASD relay. See TESTS W/CODES - 3.8L article in the ENGINE PERFORMANCE section.

ASD relay provides battery voltage to alternator field winding, electric fuel pump, fuel injectors, ignition coil and oxygen sensor heating element. PCM controls ASD relay by switching ASD relay ground circuit on and off. ASD relay is located inside Power Distribution Center (PDC), which is located in engine compartment. See label on PDC cover for relay and fuse identification.

PCM determines engine speed and synchronizes injectors from camshaft or crankshaft sensor signal. When camshaft or crankshaft sensor signal is not received with ignition switch in RUN or START position, PCM opens ASD relay ground circuit. ASD relay turns off battery voltage to electric fuel pump, fuel injectors, ignition coil and O2S sensor heating element.

If ASD relay has a suspected malfunction, replace with a known-good part and retest. If malfunction is still present, see TESTS W/CODES - 3.8L article in the ENGINE PERFORMANCE section.