Massey Ferguson A.20.1B – Hydraulic Control Module / Vehicle Control Unit (VCU): External Hydraulic Valve 2 Issue

Malfunction associated with the second external hydraulic remote (spool) valve. The underlying condition is typically an electrical communication failure (such as a short circuit, open circuit, or damaged wiring harness), a faulty spool position sensor, a failed solenoid, or a mechanically stuck spool valve that is preventing the valve from responding to electronic commands.

• 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
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726

1. 1

   Verify the hydraulic fluid (UTTO) level and condition, and check for a blocked hydraulic filter which can restrict flow.

2. 2

   Inspect the electrical connector at External Valve 2 (usually located at the rear valve stack) for corrosion, bent pins, or damaged wiring.

3. 3

   Perform a swap test: Swap the electrical connector from Valve 2 to Valve 1 or Valve 3. If the fault code changes to the corresponding valve, the issue is likely the valve's solenoid or sensor. If the code remains on Valve 2, suspect a wiring harness or ECU issue.

4. 4

   Listen for abnormal noises (whining or banging) during operation, which can indicate trapped air or internal mechanical failure of the valve.

1. 1

   Relieve Pressure

   Turn off the tractor and cycle the hydraulic remote levers/buttons to relieve all residual hydraulic pressure in the system.

2. 2

   Disconnect Battery

   Disconnect the negative battery terminal to protect the tractor's electronics.

3. 3

   Clean the Area

   Thoroughly clean the rear hydraulic valve stack to prevent dirt and debris from entering the hydraulic system during disassembly.

4. 4

   Disconnect Lines

   Label and disconnect the hydraulic hoses and electrical harness connected to Valve 2. Cap the lines immediately to prevent fluid loss and contamination.

5. 5

   Remove the Valve

   Unbolt the tie-rods or mounting bolts holding the valve stack together. Carefully slide out the faulty Valve 2 slice.

6. 6

   Install New Valve/Seals

   If rebuilding, replace the internal O-rings and faulty solenoids. If replacing the unit, insert the new valve slice. Ensure all O-rings between the valve slices are properly seated and lubricated with clean hydraulic fluid.

7. 7

   Reassemble

   Torque the valve stack bolts to OEM specifications. Reconnect the hydraulic lines and the electrical harness.

8. 8

   Bleed and Test

   Reconnect the battery, top off the hydraulic fluid, and start the tractor. Operate the remote valve several times to bleed trapped air from the system.

9. 9

   Clear Codes

   Use a compatible diagnostic tool to clear the A.20.1B / 0A.2X.1B fault code and verify it does not return.