Massey Ferguson A.42.28 – Tractor's onboard diagnostic system: External Hydraulic Valve 4 Issue

Malfunction, electrical fault, or connection problem specifically on the 4th external hydraulic remote valve (often an electric spool slice). Indicates an open circuit, short, or failure of the valve to respond to commands.

• 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

   Inspect the wiring harness and connector going to the #4 external hydraulic spool valve for corrosion, backed-out pins, or wire chafing.

2. 2

   Verify if the three-point linkage and other hydraulic remotes (Valves 1, 2, and 3) operate normally to isolate the issue to the #4 circuit and rule out the hydraulic pump.

3. 3

   Inspect the valve block for physical hydraulic fluid leaks that could be contaminating the electrical solenoid.

1. 1

   Relieve Pressure

   Turn off the tractor and actuate the hydraulic levers/controls to relieve all residual hydraulic pressure in the system before servicing.

2. 2

   Disconnect Electronics

   Unplug the electrical connector from the #4 electric spool slice.

3. 3

   Remove Hoses

   Disconnect the hydraulic hoses and fittings from the affected valve. Have a bucket ready to catch residual fluid.

4. 4

   Remove the Valve

   Unbolt the faulty external hydraulic valve (spool slice) from the valve stack.

5. 5

   Repair or Replace

   Either rebuild the valve using an OEM repair kit (if the issue is mechanical/leaking) or replace the entire electric spool slice (if the solenoid/internal electronics have failed).

6. 6

   Reinstall

   Bolt the new valve into the stack, reconnect the hydraulic lines, and plug in the electrical connector.

7. 7

   Programming

   If replacing the entire electric spool slice on modern MF tractors, the new valve may need to be programmed/calibrated to the tractor's ECU using a dealer diagnostic tool.

8. 8

   Clear Codes

   Top off the hydraulic fluid and clear the A.42.28 DTC using a compatible diagnostic tool.