Massey Ferguson A.42.22 – Auxiliary Valve Controller or Vehicle Control Unit / ECU: External Hydraulic Valve 4 Issue

This fault code indicates an electrical fault, connection problem, or operational malfunction within the circuit of the 4th external hydraulic remote (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

   Make the Tractor Safe: Lower all implements to the ground, turn off the engine, and relieve all hydraulic pressure.

2. 2

   Electrical & Wiring Inspection: Because this code often points to a "connection problem," inspect the wiring harness and electrical connector at External Hydraulic Valve 4. Look for corrosion, loose pins, or damaged wires.

3. 3

   Cross-Testing (Component Isolation): Swap the electrical connector from Valve 4 to another working valve (such as Valve 3). If the fault code changes to the new valve's circuit, the valve's solenoid/electronics are faulty. If the code remains on circuit 4, the issue lies within the wiring harness or the controller.

4. 4

   Fluid & Filter Check: Ensure the hydraulic/transmission oil is at the correct level and the hydraulic filters are not blocked, as contaminated oil or restricted flow can cause remote valve issues.

5. 5

   Mechanical Inspection: Check for external leaks around the valve poppets, O-rings, or couplers, which can cause pressure drops and erratic behavior.

1. 1

   Relieve System Pressure

   Ensure the tractor is off and actuate the remote levers/buttons in the cab to release any residual hydraulic pressure in the lines.

2. 2

   Disconnect Electronics

   Unplug the electrical wiring harness connector from External Hydraulic Valve 4.

3. 3

   Remove Hydraulic Lines

   Disconnect the hydraulic hoses and lines attached to the valve. Cap the lines immediately to prevent fluid loss and keep dirt out of the system.

4. 4

   Unbolt the Valve

   Remove the mounting bolts securing the spool valve to the hydraulic valve stack/block.

5. 5

   Replace or Repair

   If the issue is a mechanical leak, replace the faulty O-rings or poppets. If the internal solenoids or electronics have failed (common with this code), replace the entire electro-hydraulic spool valve assembly. Note: For many newer series (like the 7600/7700), Massey Ferguson often only sells the complete valve assembly rather than individual electronic components, though mechanical detents can sometimes be sourced and modified.

6. 6

   Reinstall

   Mount the new or repaired valve, torque the bolts to specification, and reconnect the hydraulic lines and electrical harness.

7. 7

   Fluid and Testing

   Top up the hydraulic fluid, start the tractor, check for leaks, and test the remote valve operation.

8. 8

   Clear Codes

   Use a compatible diagnostic tool to clear the A.42.22 / 0A.42.22 DTC from the system's memory.