John Deere 520530.03 – SCO (Front Chassis Module): Loader Boom Position Sensor Signal Voltage High

The fault indicates that the signal voltage returning from the loader boom position sensor to the controller is exceeding the maximum expected threshold. This typically points to a short to power in the sensor signal circuit, an open ground wire, or an internally failed sensor.

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

1. 1

   Inspect the wiring harness routing from the loader boom position sensor to the Front Chassis Module (SCO) for chafing, pinched wires, or damage.

2. 2

   Disconnect the sensor and inspect the pins for corrosion, moisture, or pushed-back terminals.

3. 3

   Test the sensor ground circuit for continuity to the chassis/module ground. An open ground will cause the signal voltage to pull high.

4. 4

   Test the signal wire for a short to a power source (e.g., 5V reference or 12V battery voltage).

1. 1

   Repair wiring

   If a short to power or an open ground is found during circuit testing, repair the damaged section of the wiring harness or replace the connector pigtail. Clear the codes and retest.

2. 2

   Replace sensor

   If the wiring and module outputs test good, the sensor has failed internally. Remove the faulty loader boom position sensor and install the replacement.

3. 3

   Perform calibration

   After replacing the sensor, you must perform a calibration. Use a John Deere Service ADVISOR tool (or equivalent diagnostic scanner) to run the Front Loader Boom Position Sensor Calibration routine for the SCO module to learn the new sensor's parameters.