Cummins ISB4.5 CM2150 Fault Code: 4484 PID: SPN: 4484 FMI: 7 Engine Air Shutoff Circuit – Mechanical System Not Responding or Out of Adjustment.

Posted by PerDiezel Solutions on January 20, 2026

Circuit Description
The air shutoff valve is either an original equipment manufacturer (OEM) or Cummins® installed component that shuts off the flow of air into the intake of the engine in order to prevent an engine overspeed condition. When activated, the engine control module (ECM) supplies 12 VDC to the air shutoff solenoid. This solenoid then activates the valve, closing a plate over the intake.

Component Location
The air shutoff valve is either an OEM or Cummins® installed component, and is usually located on the air intake connection.

Conditions for Running the Diagnostics
This diagnostic only runs during an Air Shutoff Valve Test.

Conditions for Setting the Fault Codes
The ECM detects that the air shutoff valve has not closed.

Action Taken When the Fault Code is Active
-The ECM illuminates the red STOP ENGINE lamp and/or the malfunction indicator lamp (MIL) immediately when the diagnostic runs and fails.

Conditions for Clearing the Fault Code
-Use INSITE™ electronic service tool to calibrate the ECM.

NOTE: The engine must be calibrated again to clear the fault code. This is done because of the hazardous operating environment and safety considerations.

-To validate the repair, the Air Shutoff Valve Test must be performed again and successfully passed.

Possible Causes
-Malfunctioning air shutoff valve solenoid
-Malfunctioning air shutoff valve
-Broken or disconnected air shutoff position switch SIGNAL wire
-Broken or disconnected air shutoff position switch RETURN wire.

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WARNING!