Massey Ferguson 0A.42.1A – Tractor Control Unit or Implement Control Module: External Hydraulic Valve 4 Issue

Indicates a fault, malfunction, or connection problem specifically located at the 4th external hydraulic remote/valve, often electrical or related to a stuck/malfunctioning valve spool.

• 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

   Inspect the wiring harness, connectors, and solenoids leading to External Hydraulic Valve 4 for corrosion, loose pins, or broken wires

2. 2

   Check the hydraulic fluid (UTTO) level and condition, and inspect the hydraulic filter for contaminants like metal shavings or dust

3. 3

   Perform a valve actuation test to check if the valve is physically stuck

4. 4

   Inspect the control valves, hoses, couplers, and seals around Valve 4 for visible leaks or pressure drops

1. 1

   Retrieve and Verify

   Use a compatible Massey Ferguson diagnostic tool to confirm code 0A.42.1A is active and check for any secondary electrical codes.

2. 2

   Isolate the Valve

   Locate External Hydraulic Valve 4 on the rear remote stack.

3. 3

   Clean and Inspect

   Clean the area around the valve to prevent system contamination. Disconnect the electrical solenoid connector and test for proper voltage/ground.

4. 4

   Unstick/Replace the Valve

   If the electrical circuit is sound but the valve is stuck, you may need to remove the valve spool assembly. In some cases, flushing contaminated fluid and replacing the filter resolves sticking. If the valve is internally damaged or leaking, remove the mounting hardware and replace the valve section.

5. 5

   Reassemble and Refill

   Install the new or repaired valve. Reconnect all hydraulic lines and electrical connectors. Top off the system with OEM UTTO hydraulic fluid.

6. 6

   Clear Codes

   Use the diagnostic interface device to clear the DTCs from the system and run a functional test of the remote to ensure proper pressure and flow.