John Deere 2798.05 – Engine Control Unit (ECU): Injector High Voltage Supply #2 Circuit Has High Resistance

The Engine Control Unit (ECU) has detected abnormally high electrical resistance in the supply circuit for a fuel injector. This indicates an open circuit, a poor connection, or a failing component, which disrupts the electrical current needed to operate the injector correctly. This issue could lead to reduced performance or failure of the engine's fuel delivery system, and the ECU may limit engine power to protect the engine from potential damage.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5090M
• 5115M
• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8245R through 8400R
• 8310RT
• 8335RT
• 8360RT
• 9470RT
• 9520RT
• 9570RT
• 6090MC
• 6100MC
• 6110MC
• 6090RC
• 6100RC
• 6110RC

1. 1

   Inspect the wiring harness leading to the #2 fuel injector for any signs of chafing, damage, wear, or disconnected/loose terminals.

2. 2

   Use a digital multimeter to measure the resistance levels within the #2 injector circuit, checking continuity from the ECU connector to the injector connector to isolate the open circuit.

3. 3

   Verify the voltage at the injection valve connector to ensure it aligns with OEM specifications and that power is reaching the injector.

4. 4

   Test the resistance across the pins of the #2 fuel injector itself to determine if the injector has failed internally (open coil).

1. 1

   Correct Electrical Faults

   If the diagnostic tests reveal a broken wire or corroded connector, repair or replace the affected section of the wiring harness or the connector pigtail.

2. 2

   Replace the Injector

   If the wiring is intact but the injector itself has an internal open circuit, safely depressurize the fuel system and replace the #2 fuel injector. (Note: When replacing an injector, it is highly recommended to replace the corresponding injector inlet connector/tube as well).

3. 3

   Reset the ECU

   After making the necessary repairs, clear the codes and reset the ECU to ensure all changes are recognized.

4. 4

   Validate Repairs

   Perform a full operational test of the fuel injection system (running the engine) to ensure it functions properly without the fault code returning.