If there is an external shutdown system on the vehicle, make sure it is not miswired and feeding voltage into the fuel shutoff supply circuit.
1)Open circuit in the engine harness, connectors, or shutoff valve.?)Fuel shutoff valve signal wire shorted to a voltage source in the harness.
1)Replace the fuel shutoff valve.2)Replace the ECM3) Replace the engine harness.
Cummins ISX CM870 (2003-06) Fault Code: 254 PID: S017 SPN: 632 FMI: 4/4 Fuel Shutoff Valve Circuit – Shorted Low. Low voltage detected at fuel shutoff valve circuit.
Cummins ISX CM870 (2003-06) Fault Code: 249 PID: P171 SPN: 171 FMI: 3/3 Ambient Air Temperature Sensor 1 Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at ambient air temperature circuit.
Cummins ISX CM870 (2003-06) Fault Code: 245 PID: S033 SPN: 647 FMI: 4/4 Fan Control Circuit – Voltage Below Normal or Shorted to Low Source. Low signal voltage detected at the fan control circuit when commanded ON.
Cummins ISX CM870 (2003-06) Fault Code: 242 PID: P084 SPN: 84 FMI: 10/10 Wheel-Based Vehicle Speed Sensor Circuit Tampering Has Been Detected – Abnormal Rate of Change. Signal indicates an intermittent connection or vehicle speed sensor (VSS) tampering.
Cummins ISX CM870 (2003-06) Fault Code: 241 PID: P084 SPN: 84 FMI: 2/2 Wheel-Based Vehicle Speed – Data Erratic, Intermittent, or Incorrect. The ECM lost the vehicle speed signal or is reading an erratic value.
Cummins ISX CM870 (2003-06) Fault Code: 234 PID: P190 SPN: 190 FMI: 0/0 Engine Crankshaft Speed/Position – Data Valid But Above Normal Operating Range – Most Severe Level. Engine speed signal indicates engine speed above engine protection limit.