Massey Ferguson 0A.8X.28 – Auxiliary Hydraulic Control Module / Vehicle Control Module: External Hydraulic Valve 8 Issue

The tractor's onboard diagnostic system has detected an electrical or communication malfunction with the 8th external hydraulic remote valve (the electric spool slice).

• 7724S
• 5712SL
• 7722S
• 7722
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Retrieve the full code using a compatible Massey Ferguson diagnostic tool to determine the specific electrical nature of the fault (e.g., low amp draw vs. open circuit).

2. 2

   Locate External Hydraulic Valve 8 in the rear remote valve stack and visually inspect the wiring harness and electrical connector for corrosion, backed-out pins, or physical damage.

3. 3

   Test the solenoid for proper resistance and verify that the tractor is sending the correct voltage and ground signals to the valve when actuated from the cab.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical shorts during service.

2. 2

   Disconnect Wiring

   Unplug the electrical connector from the faulty External Hydraulic Valve 8 slice.

3. 3

   Clean and Repair

   If the connector is corroded or wiring is damaged, clean the contacts with electrical contact cleaner or repair the harness. If the wiring is intact, the fault is internal to the electric spool slice.

4. 4

   Remove the Valve

   Relieve hydraulic system pressure. Unbolt the tie-rods/mounting bolts holding the hydraulic valve stack together and carefully remove the faulty electric spool slice.

5. 5

   Install the New Valve

   Insert the replacement electric spool slice into the stack, ensuring all O-rings are properly seated. Torque the mounting bolts to OEM specifications.

6. 6

   Reconnect and Program

   Reconnect the electrical harness. Crucial step: New electric spool slices must be programmed to the tractor's computer using a dealer diagnostic tool before they will function.

7. 7

   Test

   Clear the DTCs from the system and test the hydraulic remote for proper operation and leak-free performance.