Massey Ferguson A.41.29 – Hydraulic Control Unit or Armrest / Multifunction Control Unit: External Hydraulic Valve 4 Issue

The tractor's onboard diagnostic system has detected a malfunction on the 4th external hydraulic spool valve. This is typically an electrical connection problem, a signal out of range from the spool position sensor, or a mechanical issue preventing the valve from returning to its neutral position.

• 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

   Isolate the Implement: Try the implement on another hydraulic spool, or try a known-good implement on Spool 4. If the problem follows the hose, the implement or quick-coupler is at fault. If it stays with Valve 4, the issue is on the tractor.

2. 2

   Visual & Electrical Inspection: Inspect the wiring harness, solenoid connector, and spool position sensor at External Valve 4 for rub points, open circuits, or shorts to ground/power.

3. 3

   Mechanical Binding Check: Check if the main hydraulic distributor/spool is physically stuck and failing to return to the neutral position.

4. 4

   Reboot the System: Stop and re-run the engine. If the code is still present, the valve affected by the error code will remain electronically locked out by the controller for safety.

1. 1

   Relieve Pressure

   Turn off the tractor, lower all implements, and relieve hydraulic pressure before servicing the valve block.

2. 2

   Address Wiring/Connections

   If the diagnostic checks revealed a short or open circuit at the Valve 4 connector, clean the pins, repair any chafed wires, and apply dielectric grease. Reconnect and test.

3. 3

   Service the Spool Valve

   If the valve is mechanically sticking or leaking, remove the specific spool valve section from the hydraulic lift cover/valve stack. Clean the valve chamber, as debris can prevent the valve from sealing or returning to neutral.

4. 4

   Replace Components

   If the spool position sensor or the solenoid coil has failed (e.g., fails a resistance test), replace the electronic actuator head or the entire Valve 4 slice.

5. 5

   Clear Codes

   Use a compatible diagnostic tool to clear the error code from the control unit dashboard. Cycle the key and actuate the valve to ensure the code does not return and the valve unlocks.