Massey Ferguson B.02.21 – Hydraulic Valve Controller: Issue With Spool Position Sensor Value

This code indicates that the electronic control unit is receiving an implausible, missing, or out-of-range analog voltage signal from the hydraulic spool position sensor. It is triggered if the valve is commanded to move but the sensor does not detect the corresponding movement, or if the spool fails to return to its exact neutral position.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5400 series
• 5608-5613
• 5710SL-5713SL
• 6400 series
• 6600 series
• 6700 series
• 6711-6714
• 7400 series
• 7614-7626
• 7714-7726S
• 8600 series
• 8650-8690 SCR

1. 1

   Inspect the wiring harness leading to the spool valve for rub points, open circuits, or shorts to ground/power

2. 2

   Disconnect the sensor (often a 5-pin Molex M12 connector) and inspect for moisture, dirt, or corroded pins

3. 3

   Verify that the spool valve itself is not physically sticking due to debris or a broken return spring preventing it from returning to neutral

4. 4

   Check the sensor's voltage output to see if it changes smoothly as the valve is actuated; a dead spot or erratic voltage spike indicates a failed internal potentiometer/Hall sensor

1. 1

   Depressurize the System

   Turn off the tractor engine and cycle the hydraulic levers/joystick to relieve all hydraulic pressure in the system.

2. 2

   Locate the Sensor

   Locate the affected electronic spool valve (either the mid-mount loader valve block or the rear remote valves). The sensor is typically housed in a plastic or metallic shield bolted to the end of the valve body.

3. 3

   Disconnect Electronics

   Unplug the electrical harness connector from the position sensor.

4. 4

   Remove the Sensor

   Remove the two mounting screws securing the sensor housing to the valve body. Carefully pull the sensor straight out.

5. 5

   Inspect the Magnet/Linkage

   Ensure the permanent magnet or mechanical linkage on the end of the spool valve is intact and clean.

6. 6

   Install the New Sensor

   Seat the new position sensor onto the valve body, ensuring the anti-rotation device is properly aligned so the readings will be repeatable. Tighten the mounting screws.

7. 7

   Reconnect

   Plug the electrical harness back in, ensuring the weather seal is tight.

8. 8

   Recalibrate

   You must perform a valve calibration procedure using the tractor's diagnostic interface or dash sequence. The ECU needs to learn the new sensor's exact neutral position and end-of-stroke values to function properly.