Massey Ferguson A.70.20 – Auxiliary Valve Control Module or Basic Control ECU: External Hydraulic Valve 7 Issue

Malfunction in the 7th external hydraulic remote valve (spool valve) circuit. The issue is typically electrical or electronic in nature, such as a communication failure, a faulty solenoid, an out-of-range spool position sensor (potentiometer), or a wiring harness disconnection preventing the valve from actuating properly.

• 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

   Verify that the hydraulic fluid (UTTO) is at the correct level and that the hydraulic filters are not clogged or contaminated with metal shavings.

2. 2

   Inspect the wiring harness leading to the rear remote valve stack. Look for pinched wires, corrosion in the connector for Valve 7, or bent pins.

3. 3

   Perform a swap test by moving the electrical connector from Valve 7 to an adjacent, known-good valve (e.g., Valve 6). If the fault code changes to the corresponding code for Valve 6, the issue is within the valve's electronic actuator head. If the code remains A.70.20, the issue is in the tractor's wiring harness or the ECU.

4. 4

   Inspect the valve slice for physical leaks from the poppets or O-rings, which can cause pressure drops and trigger performance codes.

1. 1

   Relieve Pressure

   Turn off the tractor and cycle the hydraulic controls to relieve all pressure from 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 Electronics

   Unplug the electrical connector from the Valve 7 actuator.

4. 4

   Remove the Valve Slice

   Remove the lower and upper tie-rods (studs) that hold the valve slices together in the stack. Carefully pull the Valve 7 slice out, being mindful of the O-rings between the slices.

5. 5

   Replace or Rebuild

   If the issue is a leak, replace the internal O-rings and poppet seals. If the electronic actuator has failed, replace the actuator head or the entire valve slice.

6. 6

   Reassembly

   Install the new or repaired valve slice with new O-rings between the mating surfaces. Reinsert the tie-rods and torque them to the manufacturer's specification to prevent leaks.

7. 7

   Reconnect and Test

   Reconnect the wiring harness. Top up the hydraulic fluid (UTTO). Start the tractor, operate the valve to bleed any trapped air, and use a compatible diagnostic tool to clear the 0A.70.20 code.