John Deere 611.03 – ECU: Electronic Injector Wiring Shorted to Power Source

The Engine Control Unit (ECU) has detected that the wiring for the electronic fuel injectors (specifically for cylinders 1 and 4 on 4-cylinder engines, or 1, 2, and 3 on 6-cylinder engines) is shorted to a power source, typically 12 volts. This electrical fault can cause uncontrolled injector operation, leading to engine misfires, poor performance, or complete engine stalling.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5065M
• 5075M
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5095M
• 5095MH
• 5105M
• 5015ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 9230
• 9330
• 9430
• 9530
• 9630
• 8295R
• 6145J
• 6165J
• 6180J
• 6205J
• 544K
• 444J
• 544J
• 624J
• 750J
• 850J
• 3029
• 4045H
• 6068
• 6090

1. 1

   Visually inspect the injector wiring harness and the main engine harness all the way back to the ECU for chafing against engine components, heat cycling fatigue, or connector corrosion from oil ingress.

2. 2

   Perform a harness isolation test: Disconnect the injector harness at the cylinder head, turn the ignition on (and crank if necessary), and check the diagnostic display to see if the 611.03 code changes to 'Stored' or an open circuit code (e.g., 611.04). This isolates whether the short is in the harness or internal to the injector/ECU.

3. 3

   Clear all codes in the service menu, then try to start the engine to see if the 611.03 code immediately returns as active.

1. 1

   Ensure Power is Off

   Always ensure electrical power is off prior to disconnecting ECU or injector harnesses.

2. 2

   Repair or Replace Wiring

   If a short to a 12V power source is found in the wiring harness during the diagnostic checks, repair the damaged wires or replace the entire fuel injector wiring harness.

3. 3

   Test Injector Operation

   After harness repairs are made, test the injector operation to ensure they are receiving the correct voltage levels and that the internal solenoids are not shorted.

4. 4

   ECU Replacement (If Necessary)

   If the wiring harness and injectors test perfectly fine, the short may be internal to the Engine Control Unit, requiring ECU replacement and reprogramming by an authorized dealer.

5. 5

   Reset ECU

   Once the physical repair is complete, reset the ECU using a diagnostic scanner to clear the fault codes and restore normal injector control.