New Holland ENG 3267 – Engine ECU: Main relay 3 _Short circuit to Battery

The Engine ECU is detecting battery voltage on the control circuit for Main Relay 3 when it should not be present, indicating a short to a power source.

• New Holland T7 Series Tractors (e.g., T7.220, T7.235, T7.250, T7.260, T7.270)
• New Holland T8.xxx Series Tractors
• New Holland Skid Steer Loaders (SSL) and Compact Track Loaders (CTL) equipped with F5C or ISM-DI engines

1. 1

   Identify the Relay: Locate 'Main Relay 3' in the fuse/relay box. Depending on your specific machine, the fuse panel diagram may label this as the Fuel Filter Heater Relay or Fuel Pump Relay.

2. 2

   Relay Testing: Remove the relay and test the internal resistance across the coil terminals. A standard specification is typically less than 10 ohms, but an internal short will cause it to fail.

3. 3

   Circuit Testing: With the relay removed, turn the ignition ON and use a digital multimeter to check the control circuit wiring between the Engine ECU and the relay socket. You are looking for an unwanted 12V signal (short to battery) on the ground/control side.

4. 4

   Harness Inspection: Visually inspect the wiring harness between the ECU and the relay block for chafing, melted insulation, or pinched wires that could bridge the relay control wire to a constant battery power source.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent electrical damage during the repair.

2. 2

   Access the Relay Panel

   Open the main electrical center and remove Main Relay 3.

3. 3

   Replace or Repair

   If the relay failed the bench test (internally shorted), replace it with a new OEM relay. If the relay is functional, the fault lies in the wiring. Trace the wiring harness from the relay block back to the Engine ECU. Locate the section of the harness where the short to battery is occurring. Repair the damaged wire(s) by splicing and sealing with heat-shrink tubing, or replace the affected harness section.

4. 4

   Reassembly

   Reinstall the relay and reconnect the battery.

5. 5

   Clear Codes

   Turn the key to the ON position and use a diagnostic scan tool to clear the ENG 3267 fault code.

6. 6

   Verify

   Start the engine and verify that the code does not return and that the associated system (fuel filter heater or fuel pump) operates correctly.