Massey Ferguson 0A.4X.26 – TECU (Tractor Electronic Control Unit): External Hydraulic Valve 4 Issue

Malfunction in the electro-hydraulic control circuit for the 4th auxiliary remote valve (spool valve). This indicates an electrical fault (such as an open circuit, short to ground, short to power, or out-of-range voltage signal) preventing the valve's solenoid from actuating the spool correctly, or that the spool deflection is incorrect or fails to reach its center position.

• 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

   Visually inspect the 4th external hydraulic valve at the rear remote block, checking the solenoid connector for dirt, moisture, or severe rust.

2. 2

   Inspect the wiring harness leading to Valve 4 for rub points, breaks, or pinched wires that could cause a short to ground.

3. 3

   Use a multimeter to check the solenoid coil resistance and verify ground integrity.

4. 4

   Verify that the voltage reaching the valve is within the normal operating range (undervoltage < 8V or overvoltage > 36V will cause the valve to shut off).

5. 5

   Ensure the external linkage and valve are physically able to return to the center position and are not mechanically jammed.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent electrical spikes during repair.

2. 2

   Clean the Area

   Thoroughly clean the rear hydraulic valve block around Valve 4 to prevent dirt from entering the hydraulic system.

3. 3

   Remove the Solenoid/Valve Slice

   Disconnect the electrical harness from the Valve 4 solenoid. Unbolt the faulty electric spool slice or solenoid from the hydraulic block stack.

4. 4

   Install the New Part

   Fit the replacement electric spool slice or pilot pressure control solenoid. Ensure all O-rings and seals (often included in a repair kit) are properly seated. Torque the mounting bolts to OEM specifications.

5. 5

   Reconnect and Bleed

   Reconnect the electrical harness. Reconnect the battery, start the tractor, and operate the valve manually to bleed any trapped air from the slice.

6. 6

   Calibration

   Connect a compatible Massey Ferguson diagnostic tool (or use the armrest terminal if supported) to clear the 0A.4X.26 code and perform a hydraulic valve calibration. The TECU must learn the new valve's spool deflection limits; otherwise, it will throw a calibration error.