Massey Ferguson A.40.27 – Autotronic 5 / Hydraulic/Linkage Controller: External Hydraulic Valve 4 Issue

Malfunction in the circuit or operation of the 4th rear external hydraulic remote (spool valve). Typically an electrical fault such as an open circuit, a short to ground, a short to power in the valve's solenoid/actuator, a voltage signal out of range, or a CAN communication failure with the valve head.

• 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
• 7726S

1. 1

   Visual Inspection: Locate External Valve 4 on the rear hydraulic block. Inspect the wiring harness for rub points, pinched wires, or melted insulation.

2. 2

   Connector Check: Disconnect the electrical plug at the valve. Check for water ingress, corrosion, or pushed-back pins.

3. 3

   Resistance & Voltage Test: Use a multimeter to check the solenoid coil resistance and verify ground integrity. Check that the harness is delivering the correct reference voltage when the cab lever/fingertip control is actuated.

4. 4

   Swap Test (Component Isolation): Swap the electrical connector from Valve 4 to an adjacent known-good valve (e.g., Valve 3). If the fault code changes to a 'Valve 3 Issue', the problem is in the tractor's wiring harness or the Autotronic controller. If the code remains A.40.27, the electronic actuator head on Valve 4 has failed internally.

5. 5

   Mechanical Check: Ensure the external linkage and spool are in the center position and not mechanically jammed.

1. 1

   Relieve Pressure

   Turn off the tractor, lower all implements, and cycle the hydraulic levers/switches to relieve residual hydraulic pressure in the system.

2. 2

   Clean the Area

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

3. 3

   Disconnect Wiring

   Unplug the electrical connector from the faulty Valve 4 actuator.

4. 4

   Remove the Valve/Actuator

   Depending on the specific valve block design, either unbolt the electronic actuator head from the spool body (usually held by Allen bolts) or remove the entire spool valve slice from the stack.

5. 5

   Install the Replacement

   Fit the new spool valve or electronic actuator head. Ensure all O-rings are seated correctly and torque the retaining bolts to the manufacturer's specification.

6. 6

   Reconnect & Clear Codes

   Reconnect the wiring harness. Turn the ignition on and use the control unit dashboard (or a diagnostic tool like Jaltest) to delete the error code.

7. 7

   Unlock & Test

   The Autotronic system often blocks the valves when a major fault is detected. Unlock the valves via the cab terminal/dashboard and test the remote for proper double-acting operation.