Massey Ferguson 0A.21.12 – Hydraulic Control Module: External Hydraulic Valve 2 Issue

A malfunction associated with the second auxiliary hydraulic remote valve (spool valve 2). The underlying condition is typically an electrical fault (such as an open circuit, short to ground, or poor connection at the valve solenoid), a failure of the spool position sensor, or a mechanical issue preventing the valve from actuating properly.

• 7724S
• 5712SL
• 7722
• 7722S
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Inspect the wiring harness and connector at External Hydraulic Valve 2 for rubbed wires, corrosion inside the connector, or bent pins

2. 2

   Use a multimeter to check the resistance of the valve's solenoid coil to ensure it is not open or shorted to ground, and verify the module is sending the correct voltage

3. 3

   Check the live data for the 'Spool Position Sensor Value' using a diagnostic tool (such as Wintest) to verify if the value is out of range or missing

4. 4

   Ensure there is no physical debris blocking the valve linkage and that the hydraulic fluid is at the correct level and condition

1. 1

   Depressurize the System

   Turn off the tractor and actuate the hydraulic levers/buttons to relieve any residual hydraulic pressure in the system.

2. 2

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical shorts during the repair.

3. 3

   Access the Valve Block

   Locate the rear hydraulic remote valve stack. Identify Valve 2 (usually the second slice from the inlet).

4. 4

   Disconnect Electronics

   Unplug the electrical connector from the solenoid and the spool position sensor on Valve 2.

5. 5

   Remove the Valve Slice

   If the entire slice needs replacement or rebuilding, remove the tie-rod bolts holding the valve stack together. Carefully slide the faulty spool slice out, being mindful of the O-rings between the slices.

6. 6

   Repair or Replace

   If using a repair kit, replace the internal seals, O-rings, and the faulty solenoid/sensor. If replacing the entire slice, prepare the new electric spool slice.

7. 7

   Reassembly

   Install the new or repaired valve slice. Ensure all inter-slice O-rings are perfectly seated to prevent high-pressure leaks. Torque the stack tie-rod bolts to the manufacturer's specifications.

8. 8

   Reconnect

   Plug the electrical harness back into the valve. Reconnect the battery.

9. 9

   Test and Calibrate

   Start the tractor and check for leaks. Operate the valve to bleed any trapped air. Use a diagnostic tool to clear the 0A.21.12 fault code. Note: New electric spool slices often require calibration/programming to the tractor's ECU using dealer software.