Massey Ferguson A.42.1E – Onboard Diagnostic System / Hydraulic Control Module: External Hydraulic Valve 4 Issue

This indicates a malfunction, connection problem, or flow/pressure irregularity specifically isolated to the 4th external hydraulic remote (spool valve) on the tractor. The valve is responsible for directing hydraulic fluid to external implements, and the code triggers when the system detects that the valve is unresponsive, jammed, leaking, or suffering from an electrical connection failure.

• 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

   Verify the hydraulic fluid (UTTO) level and condition (look for dark, burnt, or milky fluid indicating water contamination).

2. 2

   Inspect External Valve 4 and its quick couplers for visible fluid leaks, which can cause pressure drops.

3. 3

   Inspect the wiring harness and electrical connector going to Valve 4 for frayed wires, corrosion, or a loose plug.

4. 4

   Ensure the hydraulic filters are not restricted (should be changed every 300–500 hours).

5. 5

   Use a hydraulic gauge on the Valve 4 remote coupler to test system pressure and determine if the issue is a localized valve restriction or a broader pump issue.

1. 1

   Depressurize the System

   Turn off the tractor and cycle the hydraulic controls to relieve all residual pressure in the system before beginning work.

2. 2

   Disconnect Electricals

   Unplug the electrical harness connector from External Hydraulic Valve 4.

3. 3

   Remove Hydraulic Lines

   Unbolt the hydraulic hoses/lines connected to the valve. Cap both the lines and the valve ports immediately to prevent dirt and debris from contaminating the hydraulic system.

4. 4

   Dismount the Valve

   Remove the mounting bolts securing Valve 4 to the hydraulic valve stack/manifold.

5. 5

   Rebuild or Replace

   Depending on the damage, either rebuild the valve on a clean workbench using an OEM valve repair kit (replacing O-rings and seals) or install a brand-new spool valve assembly.

6. 6

   Reinstallation

   Mount the new/rebuilt valve to the stack, torque the bolts to OEM spec, and reconnect the hydraulic lines and electrical harness.

7. 7

   Fluid and Testing

   Top up the hydraulic fluid (UTTO) as needed. Start the tractor, allow the system to warm up, and test the remote valve for proper operation and leak-free performance.

8. 8

   Clear the Code

   Use a compatible Massey Ferguson diagnostic tool to clear the A.42.1E code from the system.