John Deere 656.06 – Engine Control Unit (ECU): Fuel Injector #6 Circuit Fault

The control module detects a short circuit or abnormally low resistance in the electronic fuel injector circuit for cylinder number 6. This condition prevents the injector from operating correctly, which can lead to misfires, reduced engine power, improper combustion, and potential engine damage.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 7610
• 7710
• 7810
• 7720
• 7820
• 7920
• 9200
• 9300
• 9400
• 4930
• 4720
• 9550
• 9560
• 744H
• 744MH
• 624J
• 843J
• 643K
• 670D
• 672D

1. 1

   Inspect the wiring harness and connectors for the cylinder #6 injector for signs of chafing, melted insulation, corrosion, or exposed wires.

2. 2

   Measure the resistance in the injector circuit using a multimeter to confirm a shorted circuit (reading lower than OEM specification). Use the JT07328 Connector Adapter Test Kit to prevent terminal damage.

3. 3

   Inspect the ECU connector and diagnostic connector for dirty, damaged, or poorly positioned terminals.

1. 1

   Relieve Pressure

   Ensure the engine is off and relieve any residual fuel pressure before opening the fuel system.

2. 2

   Repair Wiring

   If the diagnostic checks reveal damaged wiring or a shorted connector leading to injector #6, repair or replace the affected wire/connector to restore proper circuit isolation.

3. 3

   Replace the Injector

   If the wiring harness tests fine, the short circuit is likely internal to the Electronic Unit Injector (EUI) itself. Remove the valve cover (if applicable to your engine model) and replace the cylinder #6 fuel injector.

4. 4

   Reassemble and Test

   Reconnect all harnesses.

5. 5

   Clear Codes

   Reset the ECU to clear the 000656.06 error code.

6. 6

   Verify Operation

   Start the engine and perform system tests to confirm that the injector operates correctly, fuel delivery is restored, and the code does not return.