Massey Ferguson A.23.20 – Autotronic Transmission/Hydraulic Controller: External Hydraulic Valve 2 Issue

Malfunction within the second rear remote hydraulic spool valve circuit. This is typically an electrohydraulic fault where the onboard diagnostic system detects a connection problem, a spool position sensor value that is out of tolerance, or an open/short circuit at the valve's solenoid.

• 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 the hydraulic/transmission oil level and condition, as contaminated oil or a blocked filter can restrict flow and cause the spool valve to stick.

2. 2

   Inspect the wiring harness leading to External Hydraulic Valve 2 for rub points, open circuits, or shorts to ground, and check the solenoid connector for dirt, corrosion, or loose pins.

3. 3

   Test the solenoid coil resistance, verify the ground integrity, and check if the spool position sensor is returning a plausible voltage signal to the Autotronic ECU.

4. 4

   Check if the electrohydraulic valve is physically stuck in the center position or if the mechanical detents have failed (a known issue on 7600 series tractors).

1. 1

   Relieve Pressure

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

2. 2

   Access the Valve Block

   Locate the rear remote valve block assembly at the rear of the tractor. Identify Valve 2 (usually the second slice in the stack).

3. 3

   Address Electrical Faults

   If the diagnostic checks revealed a wiring issue, repair the damaged harness section or replace the corroded connector plug.

4. 4

   Address Mechanical/Detent Faults

   If the valve is mechanically sticking due to worn detents (common on 7600 series), carefully remove the end cap of the spool valve. Extract the worn detent assembly and install a replacement detent kit.

5. 5

   Replace the Spool Valve

   If the internal position sensor or solenoid has failed internally and cannot be serviced separately, the entire spool valve slice must be replaced. Unbolt the tie-rods holding the valve stack together, remove Valve 2, insert the new valve slice with new O-rings, and torque the tie-rods to OEM specifications.

6. 6

   Reassemble and Clear Codes

   Reconnect the electrical harness. Top up the hydraulic/transmission fluid. Use a compatible Massey Ferguson diagnostic tool to clear the 0A.23.20 code and recalibrate the spool valve position sensor if required.