John Deere 3597.01 – Engine Control Unit (ECU): Fuel Injector High Voltage Supply Extremely Low

The Engine Control Unit (ECU) has detected that the high voltage supply to the fuel injectors is extremely low, even though the unswitched battery voltage to the ECU itself is within the correct, acceptable range. This indicates a voltage drop or open circuit between the ECU's internal injector driver and the fuel injectors, or an internal failure within the ECU itself.

• 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
• 8400R
• 8310RT
• 8335RT
• 8360RT
• 9470RT
• 9520RT
• 9570RT
• 6090MC
• 6100MC
• 6110MC
• 9570 STS
• 9670 STS
• 7180
• 7980
• 7760
• 318D

1. 1

   Inspect the main injector harness plug located on the side of the engine block (often on the right side toward the flywheel) to ensure it has not vibrated loose, disconnected, or accumulated moisture/debris.

2. 2

   Visually inspect the entire high voltage supply circuit wiring and connections to the fuel injectors for any signs of chafing, damage, wear, or loose pins.

3. 3

   Use a multimeter to measure the voltage at the fuel injector supply harness to ensure it is within the specified range according to the machine's technical manual.

4. 4

   Confirm that the unswitched battery voltage reaching the ECU is healthy and within the correct range to rule out a general machine voltage issue.

1. 1

   Repair Wiring

   If any frayed wires, corroded pins, or loose connections are found during the diagnostic checks, repair or replace the affected section of the fuel injector wiring harness.

2. 2

   Secure Connectors

   Reconnect and securely latch the main injector harness plug to the engine block.

3. 3

   Replace ECU

   If the wiring harness tests perfectly (no high resistance or shorts) and the voltage at the injectors remains extremely low while the ECU is receiving proper battery voltage, the ECU's internal injector driver module has likely failed. The ECU will need to be replaced and reprogrammed by a dealer.

4. 4

   Clear Codes and Test

   After repairs are made, reset the ECU to clear the 003597.01 fault code. Operate the engine under the same load and temperature conditions that originally triggered the code to verify that the fuel injectors are receiving the correct voltage and functioning properly.