John Deere 000647.06 – ECU: Intercooler Hydraulic Fan Drive Solenoid High Amps

The Engine Control Unit (ECU) has detected excessive electrical current (high amps) in the circuit for the intercooler hydraulic fan drive solenoid, a condition also described as low resistance in the engine fan drive circuit. This high current draw is typically caused by a short circuit to ground in the wiring harness or an internally shorted solenoid coil. When this fault is flagged, the system defaults the cooling fan to its maximum speed to prevent the engine from overheating.

• 6110M
• 6120M
• 6130M
• 5085E
• 5090E
• 5090EL
• 5100E

1. 1

   Visually inspect the wiring harness leading to the hydraulic fan drive solenoid for chafed or melted insulation, pinched wires, or corrosion. Pay close attention to the wiring leads on the solenoid coil itself.

2. 2

   Disconnect and inspect the solenoid's electrical connector for corrosion, moisture, or pushed-out pins. Clean the connector terminals and ensure a secure connection.

3. 3

   Measure the resistance across the solenoid coil terminals (expected range is typically 28 to 38 ohms) to check for an internal short.

4. 4

   With the solenoid and ECU disconnected, check the wiring harness for a short to ground by testing for continuity between each wire in the solenoid circuit and chassis ground.

5. 5

   With the key on and engine off, check for a short to power by testing for constant battery voltage on both wires at the solenoid connector.

1. 1

   Record and Clear Codes

   Note any active and stored fault codes before beginning repairs.

2. 2

   Perform Visual and Resistance Checks

   Follow the diagnostic steps outlined above.

3. 3

   Isolate the Fault

   If the solenoid coil resistance is out of specification, the solenoid is the likely cause. If the solenoid tests good, the problem is likely in the wiring harness or, less commonly, the ECU itself.

4. 4

   Replace the Faulty Component

   If the solenoid is faulty, replace it. If the wiring is damaged, repair or replace the affected section of the harness.

5. 5

   Final Verification

   After the repair, clear all fault codes from the ECU. Start the tractor and operate it to ensure the fan functions correctly and the fault code does not return.