John Deere 520529.07 – SCO (Front Chassis Module): Loader Boom Position Sensor Issue

The stored position of the loader boom position sensor has a fault or the system detects an invalid calibration state, meaning the controller cannot accurately determine the physical position of the loader boom.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 310SJ
• 410J

1. 1

   Check the signal voltage coming from the loader boom position sensor (system flags errors if voltage drops below 0.125 volts or spikes too high)

2. 2

   Inspect the wiring harness connecting the boom position sensor to the SCO (Front Chassis Module) for chafed wires, loose pins, or corrosion

3. 3

   Ensure the sensor's physical linkage to the loader boom is intact, not bent, and moving freely without binding

4. 4

   Check if the system has lost its calibration data, as the sensor may simply need to be recalibrated

1. 1

   Inspect and Clean

   Disconnect the loader boom position sensor harness. Clean the connector contacts with electrical contact cleaner and reconnect to see if the fault clears.

2. 2

   Test the Sensor

   Using a multimeter, verify the reference voltage to the sensor and the signal voltage returning to the SCO module while manually moving the boom. If the voltage does not change smoothly or is out of specification, the sensor is internally faulty.

3. 3

   Replace the Sensor

   If the sensor fails the electrical test or is physically damaged, remove the mounting hardware, disconnect the linkage, and install a new sensor.

4. 4

   Perform Calibration

   Perform a 'Front Loader Boom Position Sensor Calibration' via the tractor's display monitor or a John Deere Service ADVISOR diagnostic tool to teach the SCO module the new minimum and maximum boom positions.

5. 5

   Clear Codes

   Clear the 520529.07 code from the SCO module and test the loader functions to ensure the code does not return.