John Deere 1486 – C03: Concave Position Sensor Voltage Too Low

The voltage from the concave position sensor is below the acceptable threshold of 0.5 VDC. This indicates a potential open circuit, a short to ground in the wiring, or a failure within the sensor itself. The concave position sensor provides critical feedback to the combine's control system on the exact spacing of the concave.

• 9560 STS
• 9650 STS
• 9660 STS
• 9750 STS
• 9760 STS
• 9860 STS
• 9870STS
• 9540
• 9560
• 9580
• 9640
• 9660
• 9680
• 9660 CTS
• 9780 CTS
• 9540i
• 9560i
• 9580i
• 9640i
• 9660i
• 9680i WTS
• 9780i CTS
• S550
• S650
• S660
• S670
• S670HM
• S680
• S680HM
• S690
• S690HM
• 9410
• 9450
• 9510
• 9550
• 9570 STS
• 9610

1. 1

   Access diagnostic trouble codes on the combine's display (navigate to Cornerpost Control Unit address C03)

2. 2

   Check sensor voltage via diagnostics at address C03, 14 to observe the 'Concave Clearance (cc# 802) voltage' in real-time

3. 3

   Visually inspect the concave position sensor and wiring harness for frayed wires, loose connections, or corrosion

4. 4

   Check the linkage between the sensor and the concave for any damage or binding

1. 1

   Test the wiring harness

   Disconnect the wiring harness from the sensor. With the key in the 'RUN' position, use a multimeter to check for a 5V supply voltage at the harness connector. Check the ground pin for continuity to chassis ground, and inspect the signal wire for shorts to ground or power.

2. 2

   Test the sensor

   If the wiring is confirmed to be good, substitute the sensor with a known good part to verify if the original sensor has failed.

3. 3

   Replace the concave position sensor

   If the sensor is faulty, disconnect the electrical connector and remove mounting hardware. Install the new sensor and ensure the linkage is correctly attached.

4. 4

   Perform concave sensor zero calibration

   Access the calibration menu through the diagnostic display (dIA -> CAL -> conc). Fully close the concave until the actuator motor clicks, then save the new calibration value. This is mandatory after replacement.

5. 5

   Clear fault codes

   Clear the diagnostic trouble codes from the Cornerpost Control Unit and run the combine to ensure the fault does not reappear.