John Deere 2798.03 – ECU: Injector High Voltage Supply #2 Out of Range High

The supply voltage to the second bank or circuit of fuel injectors is excessively high, indicating a short circuit to a 12V power source (or higher voltage) within the injector supply circuit. The controller will often restrict engine functions or shut down the engine to prevent overheating and 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
• 8270R
• 8295R
• 8310R
• 8320R
• 8335R
• 8345R
• 8360R
• 8370R
• 8400R
• 8310RT
• 8335RT
• 8360RT
• 9470RT
• 9520RT
• 9570RT
• 6090MC
• 6100MC
• 6110MC
• 6090RC
• 6100RC
• 6110RC
• 7200J
• 7230J
• RM 70GO!
• RM 100GO!

1. 1

   Visually examine the wiring harness leading to the injection valves for signs of wear, chafing, melted insulation, or exposed wires that could be contacting a power source

2. 2

   Using a multimeter, probe the injector supply circuit #2 to confirm the presence of high voltage or abnormal resistance readings, and check for continuity to power (short to 12V)

3. 3

   Disconnect the main engine harness connectors at the ECU and the injector harness to inspect the pins for corrosion, moisture, or bent terminals that could bridge circuits

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent electrical shocks or further damage to the ECU.

2. 2

   Isolate the Short

   Based on your multimeter readings, trace the wiring harness from the ECU to the injector bank #2.

3. 3

   Repair or Replace Wiring

   If a specific wire is chafed and shorting to a power source, repair the wire and re-insulate it. If the internal injector wiring harness (under the valve cover) is damaged, brittle, or shorted, it must be replaced entirely.

4. 4

   Reassemble

   Reconnect all harnesses, ensuring that the injector harness is routed correctly and secured with the proper clamps to prevent future chafing.

5. 5

   Reset and Test

   Reconnect the battery. Use a John Deere Service ADVISOR diagnostic tool to clear the ECU 002798.03 fault code. Start the engine and conduct a thorough test run to ensure the injection system operates correctly and the code does not return.