John Deere 520531.04 – Front Chassis Module (SCO): Loader Bucket Position Sensor Signal Voltage Low

The system has detected that the signal voltage returning from the loader bucket position sensor is below the acceptable operational range. This typically indicates a short to ground, a faulty sensor, a broken wire, or a poor ground connection.

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

1. 1

   Inspect the wiring harness leading to the loader bucket position sensor for chafing, pinches, or rodent damage

2. 2

   Check ground connections for a loose or broken eyelet. Wiggle the battery cables and ground wires to see if the fault toggles active/inactive or if CAN bus voltages spike

3. 3

   Disconnect the sensor and check for corrosion, bent pins, or moisture inside the connector

4. 4

   Use a diagnostic tool (such as John Deere Service ADVISOR, Jaltest, or Operations Center PRO Service) to monitor the live voltage reading of the bucket position sensor

1. 1

   Preparation

   Park the tractor on a level surface. Lower the loader bucket to the lowest possible position (resting on the ground) to relieve hydraulic pressure and mechanical tension.

2. 2

   Disconnect Power

   Turn off the ignition and disconnect the battery ground cable.

3. 3

   Clean the Area

   Carefully clean the area around the position sensor to prevent dirt from entering the assembly during removal.

4. 4

   Disconnect Sensor

   Remove the protective cap (if equipped) and disconnect the electrical cable connection.

5. 5

   Remove Hardware

   Take out the mounting cap screws/hex socket screws (usually 2 to 4 screws) and remove the washers.

6. 6

   Remove Sensor

   Lift off the old position sensor. If the sensor utilizes a toothed segment or linkage, inspect it for wear and remove it if it is being replaced.

7. 7

   Install New Sensor

   Attach the new position sensor (and toothed segment, ensuring the collar is oriented correctly as seen in the direction of travel).

8. 8

   Torque Specs

   Install the hex socket screws and tighten them to the specified torque (standard specification for similar JD position sensors is 7 ± 1 N·m or 5 ± 0.7 lb-ft).

9. 9

   Reassembly

   Reconnect the electrical harness and reinstall the protective cap. Reconnect the battery.

10. 10

    Calibration

    You must perform a 'Front Loader Bucket Position Sensor Calibration' using a compatible diagnostic tool to marry the new sensor to the Front Chassis Module (SCO).