Massey Ferguson A.12.28 – Mid Mount Valve Module or Hydraulic/Implement Control Module: External Hydraulic Valve 1 Issue

Indicates a malfunction within the circuit of the first external hydraulic remote valve, typically triggered by a connection problem on the hydraulic valve, an implausible or out of range Spool Position Sensor value, or a loss of communication between the Dash and the Mid Mount Valve Module.

• 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

   Inspect the wiring harness, pins, and connectors leading to External Hydraulic Valve 1 for corrosion, moisture, or wire breaks

2. 2

   Use a compatible diagnostic tool to read the live data values of the Spool Position Sensor for Valve 1, looking for erratic or missing voltage signals

3. 3

   Verify that the Mid Mount Valve Module is communicating properly with the Dash

1. 1

   Relieve Pressure

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

2. 2

   Access the Valve

   Locate External Hydraulic Valve 1, typically found in the rear remote valve stack or the mid-mount block.

3. 3

   Clean and Reconnect

   Disconnect the electrical harness from the valve's spool position sensor and solenoid. Clean the contacts with electrical contact cleaner, reconnect, and check if the code clears.

4. 4

   Replace Faulty Component

   If the wiring is intact but the spool position sensor value remains out of specification, the sensor or the entire valve section must be replaced. Unbolt the affected valve section from the hydraulic stack (be prepared to catch leaking hydraulic fluid).

5. 5

   Install New Valve

   Mount the replacement external hydraulic valve or sensor, ensuring O-rings are properly seated. Torque the stack bolts to OEM specifications.

6. 6

   Reassemble and Refill

   Reconnect the wiring harness. Check the tractor's hydraulic fluid level and top off with Massey Ferguson approved oil (e.g., CMS M1143 or M1144).

7. 7

   Clear Codes

   Use a compatible diagnostic tool to clear the A.12.28 DTC from the system and test the remote valve for proper operation.