Massey Ferguson A.1X.28 – Armrest Controller or Mid Mount Valve Module / Hydraulic Valve Controller: External Hydraulic Valve 1 Issue

Malfunction within the first external hydraulic remote valve (spool valve) circuit. Typically triggered by an issue with the spool position sensor value, a loss of CAN-bus communication, or an electrical fault such as an open or short circuit.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726
• 8670
• 8690

1. 1

   Check if other hydraulic valves (Valve 2, 3, etc.) are operating correctly to rule out a broader CAN-bus communication failure between the Armrest Controller and Valve Module.

2. 2

   Visually inspect the wiring harness and connectors leading to External Hydraulic Valve 1 at the rear of the tractor for chafed wires, corrosion, or loose pins.

3. 3

   Test the spool position sensor voltage and resistance using a multimeter to ensure values are within the normal operating range.

4. 4

   Perform a swap test by temporarily connecting Valve 1's electrical connector to Valve 2. If the fault code changes to Valve 2, the issue is inside the valve's solenoid/sensor. If it remains on Valve 1, the issue is in the wiring harness or Armrest Controller.

1. 1

   Relieve Pressure

   Lower all implements to the ground, turn off the engine, and cycle the hydraulic levers/joystick to relieve residual hydraulic pressure.

2. 2

   Disconnect Battery

   Disconnect the negative battery terminal to prevent electrical shorts during repair.

3. 3

   Access the Valve Stack

   Locate the external hydraulic valve block (typically at the rear of the tractor above the rear axle). Clean the area thoroughly to prevent dirt from entering the hydraulic system.

4. 4

   Remove Electrical Connections

   Unplug the solenoid and spool position sensor connectors from External Valve 1.

5. 5

   Remove the Faulty Valve

   Unbolt the tie-rods or mounting bolts holding the valve slice to the main hydraulic block. Carefully separate Valve 1 from the stack, ensuring you do not lose or damage the O-rings between the valve slices.

6. 6

   Install the New Valve/Sensor

   If replacing the whole slice, install the new External Hydraulic Valve 1. If only replacing the solenoid or position sensor, unbolt the faulty electronic component from the mechanical spool and install the new one.

7. 7

   Reassemble and Torque

   Reinstall the mounting bolts/tie-rods and tighten them to the OEM specified torque (refer to the specific model's service manual for exact torque specs to prevent spool binding or leaks).

8. 8

   Reconnect and Calibrate

   Reconnect the electrical harnesses, reconnect the battery, and use a dealer diagnostic tool to clear the A.1X.28 code and calibrate the new spool valve limits.