Auto Shutdown Relay
Auto Shutdown (ASD) relay is located in Power Distribution Center (PDC). PDC is located in engine compartment. See Fig 1 and Fig 2 . ASD relay location may also be determined by referring to the PDC cover label.
The ASD relay is used to connect the oxygen sensor heater elements, oxygen sensor heater relay, ignition coil(s) and fuel injectors to a 12-volt power supply. This input is used only to sense that the ASD relay is energized. If the Powertrain Control Module (PCM) does not see 12 volts at this input when the ASD should be activated, it will set a Diagnostic Trouble Code (DTC). The ASD relay supplies battery voltage (12+ volts) to the fuel injectors and ignition coil(s). With certain emission packages it also supplies 12 volts to the oxygen sensor heating elements and the oxygen sensor heater relay. The ground circuit for the coil within the ASD relay is controlled by the PCM. The PCM operates the ASD relay by switching its ground circuit on and off. The ASD relay will be shutdown, meaning the 12-volt power supply to the ASD relay will be deactivated by the PCM if the ignition key is left in the ON position. This is if the engine has not been running for approximately 1.8 seconds.