Case IH t14 – Engine Electronic Control Unit (ECU) or Pump Control Unit (PCU): Test Shut Off Paths, Shorted To High Source

The engine's fuel shut-off circuitry (specifically the test paths used by the controller to verify the shut-off signal) is detecting an abnormally high voltage, meaning the circuit is shorted to a high power source.

• MXM
• MXM120
• MXM130
• MXM140
• MXM155
• MXM175
• MXM190
• MX Series
• TG Series
• Maxxum
• TM Series
• TM115-TM165

1. 1

   Turn the Power OFF and Keyswitch OFF, then disconnect the battery or pull the relevant fuse to prepare for testing

2. 2

   Disconnect the connectors at both ends of the fuel shut-off circuit (at the ECU/PCU and at the fuel shut-off solenoid) to isolate the circuit

3. 3

   Visually inspect the affected connectors and the harness outer covering for chafing, melted insulation, or exposed wires that could be bridging to a 12V power source

4. 4

   Set your multimeter to measure resistance (Ohms), use the black lead to make contact with a clean, plated metal part on the chassis to ensure a good ground, and use the red meter lead to probe the connector pins one at a time

5. 5

   Using a multimeter set to DC Voltage, turn the key ON (engine off) and probe the shut-off path pins. If voltage is present on the signal return/test path, a short to high source is confirmed

1. 1

   Trace the Short

   Follow the harness routing from the fuel shut-off solenoid back to the ECU/PCU to locate the exact point of the short circuit.

2. 2

   Repair the Wiring Harness

   If a short is found in the wiring, use a CNH-approved harness repair kit. Use the correct pin removal tool to extract damaged pins from the connector. Cut the damaged wire, splice in a new section of the required length, and re-pin it into the connector.

3. 3

   Test the Solenoid

   If the wiring harness tests perfectly, the internal coil of the fuel shut-off solenoid may have failed and shorted internally. Test the resistance across the solenoid terminals; if it is out of specification or shorted, replace the solenoid.

4. 4

   Clear Codes and Verify

   Reconnect all affected connectors. Turn the keyswitch ON and verify if the t14 code clears. Start the engine to ensure the fuel shut-off path operates normally.