John Deere 520529.31 – Front Chassis Module (SCO): Loader Boom Position Sensor Issue

This fault code indicates that the voltage ratio between Channel 1 and Channel 2 of the loader boom position sensor is mismatched or out of range.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R

1. 1

   Inspect the loader boom position sensor, its mounting bracket, and linkage for physical damage, bending, or debris buildup that could restrict its movement.

2. 2

   Inspect the wiring harness routing from the Front Chassis Module (SCO) to the boom position sensor. Look for chafed wires, pinched harnesses, or corrosion inside the connector pins.

3. 3

   Back-probe the sensor connector to verify the 5V reference and ground. Monitor the signal voltage on both Channel 1 and Channel 2 while manually moving the boom. The voltages should change smoothly without dropping out, and their ratio must remain consistent.

1. 1

   Repair Wiring

   If the diagnostic checks reveal a short, open circuit, or corroded connector on either Channel 1 or Channel 2, repair the wiring harness or replace the pigtail connector. Clear the codes and test operation.

2. 2

   Replace the Sensor

   If the wiring is intact but the voltage ratio between the two channels remains out of specification, the internal potentiometers/hall-effect tracks of the sensor have failed. Remove the mounting hardware, disconnect the harness, and install a new Loader Boom Position Sensor.

3. 3

   Perform Calibration

   Use the tractor's CommandCenter display or John Deere Service ADVISOR to run the automated calibration procedure so the SCO module learns the new sensor's minimum and maximum voltage limits.