John Deere 3020 – RCU: Unloading Auger Engage Activated Without Command

The control system has detected that the unloading auger engage circuit is active (receiving power) when it has not been commanded by the control unit RCU via the unloading auger drive switch. This indicates an unexpected activation of the unloading auger engage circuit, which can be caused by an electrical short circuit, a faulty switch, a malfunctioning control unit, or a mechanical issue causing unintended engagement.

• 9470 STS
• 9570 STS
• 9670 STS
• 9770 STS
• 9870 STS
• 9560 STS
• 9660 STS
• 9760 STS
• S660
• S670
• S680
• S690
• S760
• S770
• S780
• S790
• 9540 WTS
• 9560 WTS
• 9580 WTS
• 9640 WTS
• 9660 WTS
• 9680 WTS

1. 1

   Verify operator procedures: ensure the operator is squarely on the seat and the road transport disconnect switch is in the 'field' position

2. 2

   Check for other active fault codes related to the RCU, wiring, or sensors

3. 3

   Inspect the wiring harness and connectors for the unloading auger switch, solenoid, and sensors for damage, corrosion, or loose connections (including checking for an unplugged GreenStar receiver extension cable)

4. 4

   Check the unloading auger drive switch for internal failure causing a constant 'on' signal

5. 5

   Inspect drive belts to ensure they are not stretched or the incorrect size (e.g., belts 1 inch too short can cause random engagement)

6. 6

   Check unloading auger solenoid magnetization by seeing if a wrench sticks to it when commanded off, indicating it is receiving uncommanded power

1. 1

   Safety First

   Set the parking brake, shut off the engine, and remove the key before any inspection or repair.

2. 2

   Run Calibration Procedures

   Perform the unloading auger engage system calibration and swing time calibration, which can sometimes resolve engagement issues.

3. 3

   Test the Unloading Auger Switch

   Disconnect the switch and test for continuity to ensure it is opening and closing the circuit correctly and is not shorted internally.

4. 4

   Test the Unloading Auger Solenoid

   Disconnect the electrical connector and check for voltage with the auger commanded OFF. If voltage is present, locate and repair the short in the wiring harness or replace the RCU. If no voltage is present, inspect the solenoid valve or hydraulic block for mechanical issues like a broken internal spring.

5. 5

   Adjust the Drive Cylinder

   If the auger drive will not shut off and belts have stretched, adjust the cylinder rod stop by marking the current position, loosening the locknut and bolts, sliding the stop, and retightening.

6. 6

   Inspect the Control Unit

   If all other possibilities are ruled out, have a qualified technician diagnose the Right-hand Control Unit (RCU) or related module for internal faults.