Massey Ferguson B.01.21 – Mid Mount Valve Module: Issue With Spool Position Sensor Value

The control module is receiving an out-of-range, erratic, or missing signal from the sensor that monitors the physical position of the hydraulic spool valve.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S

1. 1

   Check Hydraulic Oil and Filters for contamination or blockages that can restrict flow and cause the spool valve to stick.

2. 2

   Inspect Wiring and Connectors leading to the mid-mount electro-hydraulic valve for chafed wires, loose pins, or corrosion at the sensor connector.

3. 3

   Check for Valve Sticking to ensure the spool valve itself is not physically jammed due to debris or mechanical wear.

4. 4

   Test Sensor Voltage to verify that the sensor is receiving the correct reference voltage from the module and that the signal wire has continuity back to the ECU.

1. 1

   Relieve Hydraulic Pressure

   Ensure the tractor is turned off and all hydraulic pressure is relieved from the system before servicing the valves.

2. 2

   Clean the Area

   Thoroughly clean the mid-mount valve block to prevent dirt from entering the hydraulic system during disassembly.

3. 3

   Remove the Sensor

   Disconnect the electrical harness from the spool position sensor. Unbolt and carefully remove the sensor from the spool valve housing.

4. 4

   Inspect the Spool

   Check the exposed end of the spool for scoring or sticking. If the valve is sticking, the entire valve block may need to be removed, disassembled, and cleaned.

5. 5

   Install the New Sensor

   Fit the replacement spool position sensor and torque the mounting bolts to OEM specifications. Reconnect the wiring harness.

6. 6

   Recalibrate the Valves

   After replacing the sensor, you must use a compatible diagnostic tool to perform a valve calibration.

7. 7

   Test Operation

   Start the tractor, operate the joystick, and verify that the loader/remotes respond smoothly without throwing the B.01.21 code.