Circuit DescriptionThe air shutoff valve is an optional component used to shutdown the engine in the event of an engine overspeed condition. It can be closed via a manual shutdown switch or via an ECM command.

Component LocationThe engine air shutoff valve location can vary depending on the OEM. Refer to the OEM service manual.

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

Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the engine speed was greater than 2500 RPM for 0.25 seconds, or the operator manually tripped the engine air shutoff valve.

Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and fails.The air shutoff valve closesThe engine will be shut down.

Conditions for Clearing the Fault CodeThe air shutoff valve must be reset to the open position.To validate the repair, perform a key cycle, 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 immediately 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, as well as extinguish the MIL for OBD applications.

Shop TalkThis fault code indicates that the engine has been shut down via the engine air shutoff valve. This can occur automatically (engine overspeed condition) or manually (activating the engine air shutoff valve switch in the cab). In either case, this fault code will become active until the valve de-activated.

Possible Cause:1) Engine damage2) Crankshaft engine speed sensor, or Camshaft engine position sensor3) ECM failure