Circuit DescriptionThe Electronic Control Module (ECM) Idle Shutdown feature has an optional parameter for a shutdown accessory relay. When this parameter is set to ?Installed?, the ECM sends a signal to energize the relay and turn off vehicle accessories during idle shutdown events. The idle shutdown relay return circuit varies by Original Equipment Manufacturer (OEM). The return circuit can be returned to the ECM through the ECM Return (General) or connected directly to ground. Refer to the OEM service manual to determine the grounding configuration.

Component LocationThe idle shutdown relay location varies by OEM. Refer to the OEM service manual to determine the location.

Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position.

Conditions for Setting the Fault CodesThe idle shutdown relay Pulse Width Modulated (PWM) signal is detected by the ECM to be at 0-VDC when the PWM voltage is turned on.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.The accessories controlled by the idle shutdown relay will be disabled.Conditions for Clearing the Fault CodeTo validate the repair, start the engine and let it idle for 1 minute.The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.The ?Reset All Faults? command in INSITE? electronic service tool can be used to clear active and inactive faults.

Shop TalkThe ECM monitors the voltage level on this circuit. This fault code is logged if it detects a low voltage when the relay signal is commanded on. This fault code can be caused by a short circuit to ground in the idle shutdown relay, OEM harness, or connectors.

Reference the appropriate OEM wiring diagram when troubleshooting circuits that utilize wiring supplied by the OEM.

For intermittent power supply and datalink communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.

Possible Cause:1) Idle Shutdown relay failure2) OEM harness3) ECM calibration