Massey Ferguson A.20.12 – Onboard Diagnostic System / Main Vehicle Control Unit: External Hydraulic Valve 2 Issue

This code is generated when the tractor's onboard diagnostic system detects a signal out of range, a circuit problem, or an uncorrectable system condition on the second external hydraulic remote (spool) valve.

• 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

   Check the solenoid connector on External Hydraulic Valve 2 for corrosion, moisture, or loose pins. Inspect the wiring harness leading to the valve for rub points or breaks.

2. 2

   Measure the resistance of the valve's solenoid coil with a multimeter to ensure it is not open or shorted. Verify the ground integrity of the circuit.

3. 3

   Ensure the tractor's battery and alternator are providing proper voltage, as low voltage during operation can trigger false hydraulic valve codes.

4. 4

   Verify that the hydraulic fluid is at the correct level and that the hydraulic filter (often a 20-micron cartridge filter) is not clogged, which could cause pressure drops.

1. 1

   Retrieve and Verify

   Connect a compatible Massey Ferguson diagnostic tool to confirm code 0A.20.12 is active and check for any secondary codes (like low voltage or CAN bus errors).

2. 2

   Isolate the Fault

   Swap the electrical connector from External Valve 2 to External Valve 1 (if the harness allows). If the fault code changes to Valve 1, the issue is in the wiring harness or controller. If the fault remains on Valve 2, the issue is the valve solenoid or the valve body itself.

3. 3

   Replace the Solenoid/Valve

   If the solenoid fails the resistance test or is receiving power but not actuating, remove the retaining nut/screws on the spool valve solenoid and replace it. If the spool itself is mechanically seized inside the valve block, the entire External Hydraulic Valve 2 section may need to be removed, cleaned, or replaced.

4. 4

   Reassemble and Bleed

   Reinstall the components, ensuring all O-rings are seated properly. Top off hydraulic fluid if any was lost during the repair.

5. 5

   Clear Codes

   Use the diagnostic interface device to clear the DTCs from the system and cycle the tractor's key to ensure the code does not return. Test the remote valve with an implement to confirm operation.