Massey Ferguson A.42.12: External Hydraulic Valve 4 Issue

Malfunction within the 4th external hydraulic remote valve (spool valve) circuit, typically indicating an electrical continuity issue, a sticking valve spool, or a communication failure between the valve's solenoid and the tractor's diagnostic system.

• 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 electrical wiring harness and the connector plugging into External Hydraulic Valve 4 for corroded pins, frayed wires, or loose connections

2. 2

   Check the hydraulic fluid level and condition (ensure it is clean, has no milky appearance or burnt smell, and is the correct UTTO)

3. 3

   Inspect the valve block, quick couplers, and hoses for visible leaks that can cause pressure drops

4. 4

   Check if the valve is sticking or jamming due to debris or internal wear, which can cause the solenoid to overdraw current

1. 1

   Relieve Pressure

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

2. 2

   Clean and Reconnect

   Disconnect the electrical harness from Valve 4. Clean the contacts with electrical contact cleaner, apply dielectric grease, and securely reconnect it. Clear the code with a diagnostic tool to see if the fault returns.

3. 3

   Valve Removal

   If replacement or internal cleaning is needed, remove the mounting bolts securing the #4 valve section to the hydraulic base plate/lift cover. Carefully separate the valve, ensuring that you do not dislodge the internal standpipe from its seat in the hydraulic pump.

4. 4

   Service the Valve

   If the valve spool is sticking, clean the spool and replace the internal O-rings/seals. If the solenoid or valve body has failed electrically, the valve section must be replaced.

5. 5

   Reinstallation

   Fit the new or repaired valve back onto the base plate. Ensure the standpipe and all O-rings are correctly located in their seats.

6. 6

   Secure and Test

   Tighten the mounting bolts to the specified torque. Reconnect the electrical harness.

7. 7

   Fluid and Filter

   Top up the hydraulic fluid (UTTO) and replace the hydraulic filter if it has been more than 300–500 hours since the last change.

8. 8

   Clear Codes

   Use a compatible Massey Ferguson diagnostic tool to clear the 0A.42.12 code and test the remote valve operation.