Massey Ferguson A.50.18 – EHR (Electronic Hitch/Hydraulic Control) module or Autotronic control module: External Hydraulic Valve 5 Issue

Malfunction in the 5th external hydraulic remote (spool valve) circuit, typically triggered by an electrical connection problem (such as an open or short circuit in the wiring/solenoid) or a restricted operation/mechanical binding within the mini-hydraulics system.

• 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

   Visual & Harness Inspection: Inspect the wiring harness leading to the #5 external hydraulic valve block at the rear of the tractor. Look for chafed wires, corrosion, or loose connector pins.

2. 2

   Solenoid Resistance Test: Use a multimeter to check the resistance of the solenoid coil on Valve 5. Compare it against the specifications for adjacent, working valves (e.g., Valve 4 or 6).

3. 3

   Mechanical Binding Check: Ensure the spool valve isn't physically jammed by debris. Test this by manually overriding the valve (if equipped with a manual override pin) to see if it moves freely.

4. 4

   Hydraulic Fluid Verification: Verify that the hydraulic fluid is at the correct level and that the hydraulic filters are not clogged.

1. 1

   Depressurize the System

   Lower all hydraulic implements to the ground. Turn off the tractor and cycle the hydraulic levers/joystick to relieve any residual pressure in the system.

2. 2

   Clean the Area

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

3. 3

   Disconnect Electricals

   Unplug the electrical connector from the Valve 5 solenoid.

4. 4

   Remove the Valve Slice

   Unbolt the tie-rods or mounting bolts holding the spool valve stack together. Carefully slide out the faulty #5 electric spool slice (or remove the solenoid if it is serviceable separately).

5. 5

   Prep and Install

   Clean the mating surfaces. Install the new spool valve slice using new O-rings between the valve sections to prevent internal/external leaks.

6. 6

   Reassemble

   Torque the valve stack tie-rods to the OEM specification found in your service manual to ensure proper sealing without warping the spools.

7. 7

   Reconnect and Test

   Reconnect the electrical harness. Top up the hydraulic fluid if any was lost. Start the tractor, operate the valve to bleed out trapped air, and check for leaks.

8. 8

   Clear Codes

   Use a compatible diagnostic tool (such as AGCO's EDT or Noregon JPRO) to clear the 0A.50.18 code from the EHR/Autotronic module. Note: Some electric spool slices require calibration/programming to the tractor's module upon installation.