John Deere 1075.05 – Engine Control Unit (ECU): Low Pressure Fuel Pump Circuit Has High Resistance

The Engine Control Unit (ECU) monitors the low-pressure fuel pump control circuit. When it detects high electrical resistance, it indicates an open circuit is present. Because of this open circuit, the ECU cannot energize the lift pump relay to power the electric fuel transfer pump.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 9230
• 9330
• 9430
• 9530
• 9630
• 8130
• 8230
• 8330
• 8430
• 8530
• 8R series
• 9R series
• 9660 STS
• 9760 STS
• S650
• S660
• S670
• S770
• 748H Skidders
• 4930

1. 1

   Visually inspect the electric fuel pump and wiring harness for broken wires, rubbed-through insulation, or a disconnected/corroded 6-way connector.

2. 2

   Run an interactive harness diagnostic test using John Deere Service Advisor.

3. 3

   Isolate the pump by unplugging the 6-way connector and rerunning the test. If the code reoccurs, the open circuit is in the harness or ECU. If it does not, the pump has an internal open circuit.

4. 4

   Check the transfer pump duty cycle using Service Advisor (typical values are 15-20 while running without a load).

1. 1

   Preparation

   Turn off the engine, remove the key, and disconnect the battery to prevent electrical shorts.

2. 2

   Access the Pump

   Locate the electric lift pump/fuel transfer pump, which is mounted on the primary fuel filter base assembly.

3. 3

   Harness Repair (If Applicable)

   If diagnostics pointed to a harness failure, trace the wiring from the pump connector back to the ECU. Repair any broken wires or replace damaged connector pins.

4. 4

   Pump Replacement (If Applicable)

   Clean the area around the fuel filter base to prevent dirt from entering the fuel system. Disconnect the electrical connector from the lift pump. Pinch off or plug the incoming fuel lines to prevent excessive fuel drainage, then disconnect the fuel lines from the pump. Remove the mounting bolts securing the electric lift pump to the filter base and remove the faulty pump. Install the new electric lift pump with new O-rings/seals. Reconnect the fuel lines and the electrical connector.

5. 5

   System Priming

   Reconnect the battery. Turn the key to the ON position (without starting the engine) to allow the new electric lift pump to prime the fuel system.

6. 6

   Verification

   Clear the ECU 001075.05 fault code using a diagnostic tool. Start the engine, check for fuel leaks, and verify that the code does not return.