Massey Ferguson A.21.20 – Onboard Diagnostic System / Main Vehicle Control Module: External Hydraulic Valve 2 Issue

Malfunction in the second rear remote hydraulic spool valve circuit. This indicates restricted oil flow, a pressure problem, a stuck/jammed spool valve, or an electrical connection issue preventing the valve from responding to operator inputs.

• 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

   Check hydraulic and transmission filters for blockages or contaminated oil, which can cause slow or weak remote hydraulics.

2. 2

   Inspect quick connect couplers for wear or trapped foreign matter that could restrict flow or cause hoses to disconnect under pressure.

3. 3

   Check the wiring harness and electrical connector at External Valve 2 for connection issues.

4. 4

   Inspect spool valve detents to see if they have rusted or jammed, making the valve unresponsive.

5. 5

   Check for internal leaks (e.g., implements dropping overnight) indicating worn internal O-rings or seals within the valve block.

1. 1

   Relieve System Pressure

   Lower all implements to the ground and turn off the tractor to relieve hydraulic pressure before servicing.

2. 2

   Disconnect Electrical Harness

   Carefully unplug the electrical connector from External Hydraulic Valve 2. Clean the contacts with electrical contact cleaner to rule out a simple short or bad ground.

3. 3

   Remove Quick Couplers

   Unthread the quick connect couplers from the valve body. Inspect the female body halves for internal wear or debris. Replace if worn.

4. 4

   Extract the Spool Valve

   Unbolt the External Hydraulic Valve 2 assembly from the rear hydraulic block.

5. 5

   Service the Detents

   If the valve is mechanically stuck, you may be able to rebuild the detents.

6. 6

   Reinstall and Test

   Install the new or rebuilt valve using fresh O-rings. Reconnect the hydraulic lines and electrical harness. Top off the hydraulic fluid, start the tractor, and cycle the remote valve to bleed air and verify operation.