Massey Ferguson 0A.21.20 – Hydraulic Control Module / Mid-Mount Valve Module: External Hydraulic Valve 2 Issue

A malfunction in the second external hydraulic spool valve circuit. The underlying condition is typically a connection problem on the hydraulic valve, a faulty spool position sensor value, or a mechanical issue such as the valve sticking or jamming due to debris or internal wear.

• 7724S
• 5712SL
• 7722
• 7722S
• 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

   Verify the hydraulic fluid (UTTO) is at the correct level and free of heavy contamination (metal shavings or dust) which can cause valves to stick.

2. 2

   Check around External Valve 2 for visible fluid leaks at the quick couplers, hydraulic hoses, or piston seals.

3. 3

   Inspect the electrical harness connecting to the External Hydraulic Valve 2 actuator and spool position sensor for damaged wires, corrosion, or loose pins.

4. 4

   Manually move the control lever back and forth to check if the valve is physically jammed and to temporarily release a stuck spool valve.

1. 1

   Depressurize the System

   Turn off the tractor and cycle the hydraulic levers to relieve all pressure from the hydraulic system before beginning work.

2. 2

   Disconnect Electricals

   Unplug the wiring harness from the External Hydraulic Valve 2 actuator and spool position sensor. Clean the contacts with electrical contact cleaner. If the harness is damaged, splice or replace the affected wiring.

3. 3

   Remove the Valve

   If the electrical connection is sound but the code persists, unbolt the External Hydraulic Valve 2 assembly from the valve stack/block.

4. 4

   Clean and Inspect

   Flush the valve with clean hydraulic fluid. Inspect the internal spool for scoring, wear, or debris.

5. 5

   Replace Components

   If the spool is scored or the position sensor has failed, replace the External Hydraulic Valve 2 assembly or the specific sensor/actuator.

6. 6

   Reassemble and Service

   Mount the new/cleaned valve, replace the hydraulic filter (highly recommended when opening the system), and top off the UTTO hydraulic fluid.

7. 7

   Clear Codes

   Use a compatible Massey Ferguson diagnostic interface tool to clear the 0A.21.20 code from the system. Test the hydraulic remote to ensure proper operation.