Case IH 255 – Engine Control Module (ECM) / ENG: Fuel Shutoff Valve Voltage too high

The engine controller is detecting a voltage on the fuel shutoff valve circuit that exceeds the normal operating parameters. This is typically caused by a short to a power source in the wiring harness or an internal short within the fuel shutoff valve solenoid itself.

• MX Magnum
• STX Steiger
• Case IH Magnum series
• Case IH Steiger series
• Case IH Puma series
• Puma 125
• Case IH MX series

1. 1

   Visually inspect the wiring harness running from the Engine Control Module (ECM) to the fuel shutoff valve for chafed wires, melted insulation, or pinched areas that could cause a short to a 12V power source.

2. 2

   Disconnect the fuel shutoff valve connector, turn the key to the ON position, and use a multimeter to check the voltage at the harness connector. Presence of voltage indicates the harness is shorted to power.

3. 3

   Measure the resistance (Ohms) across the pins of the fuel shutoff valve solenoid. An abnormally low resistance reading indicates the coil is internally shorted.

4. 4

   Inspect the ECM connector pins for corrosion, moisture, or bent pins that could be bridging circuits.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a short to power in the harness, repair the damaged section of wiring using proper weather-sealed connectors, or replace the affected harness section.

3. 3

   Replace the Valve

   If the fuel shutoff valve is internally shorted: Clean the area around the injection pump/fuel shutoff valve to prevent debris from entering the fuel system. Unbolt and remove the faulty fuel shutoff valve. Install the new fuel shutoff valve (lubricate any O-rings with clean diesel fuel if applicable) and tighten to OEM torque specifications.

4. 4

   Reassembly

   Reconnect the electrical connector to the valve.

5. 5

   Test

   Reconnect the battery, turn the ignition ON, and clear the stored fault codes. Start the engine to verify the repair and inspect the valve area for any fuel leaks.