John Deere 653.06 – Engine Control Unit (ECU): Injector Number 3 Low Resistance Error

The Engine Control Unit (ECU) has detected a low electrical resistance condition in the circuit for the number 3 fuel injector. This indicates a potential short circuit in the injector's internal windings, the wiring harness leading to the injector, or the injector's driver circuit within the ECU. This condition allows electrical current to flow with less opposition than expected, preventing the injector from operating correctly and resulting in improper fuel delivery to the third cylinder.

• 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
• 6120-6420
• 6230
• 6330
• 6430
• 7610
• 7710
• 7810
• 7630
• 7730
• 7830
• 7930
• 8330
• 9230-9630 series
• 6M series
• 750J
• 850J
• 444J
• 544J
• 624J
• 130G
• 160GLC
• 180GLC
• 250GLC
• 1070E
• 1170E
• 4930

1. 1

   Cycle the power by restarting the engine to verify if the active code reappears, ruling out a temporary communication glitch.

2. 2

   Inspect the engine wiring harness between the ECU and the #3 injector for chafed wires, melted insulation, or pinched lines that could cause a short circuit to ground or to another wire.

3. 3

   Disconnect the #3 injector and use a multimeter with a proper connector adapter test kit to measure the resistance across the injector solenoid pins. Compare to OEM specifications (near zero indicates an internal short).

1. 1

   Safety First

   Turn off the engine, disconnect the battery, and allow the engine to cool. Relieve fuel system pressure before opening any lines, as high-pressure fuel can penetrate the skin and cause severe injury.

2. 2

   Access the Injector

   Depending on the engine model (e.g., 10.5L/12.5L), the electronic unit injectors may be located under the engine valve cover. Remove the valve cover if necessary.

3. 3

   Isolate the Fault

   Disconnect the electrical connector at the #3 injector. Test the harness side for shorts. If the harness is damaged, repair or replace the engine wiring harness. If the harness tests good, the injector itself has failed.

4. 4

   Replace the Injector

   Remove the hold-down clamp and extract the faulty #3 injector. Clean the injector cup/bore thoroughly.

5. 5

   Install New Injector

   Install the replacement injector with new O-rings. Torque the hold-down bolt to exact OEM specifications.

6. 6

   ECU Calibration

   Reconnect the wiring and battery. Use a diagnostic tool (like John Deere Service ADVISOR) to program the new injector's calibration QR code/trim code into the ECU to prevent secondary fault codes and poor engine performance.

7. 7

   Test

   Clear the ECU fault codes, prime the fuel system, and test-run the engine to verify the repair.