Massey Ferguson A.12.20 – Mid Mount Valve Module: External Hydraulic Valve 1 Issue
Issue description
Malfunction in the first external hydraulic remote valve (spool valve). The underlying condition is typically an electronic failure, such as an issue with the spool position sensor value, a failure in valve calibration, or a communication loss with the valve module.
Applies to these machines
40 machines- 5710SL
- 5711SL
- 5712SL
- 5713SL
- T4
- 7714
- 7715
- 7715S
- 7716
- 7716S
- 7718
- 7718S
- 7719
- 7720
- 7720S
- 7722
- 7722S
- 7724
- 7724S
- 7726
- 7726S
- 7614
- 7615
- 7616
- 7618
- 7619
- 7620
- 7622
- 7624
- 7626
- 5608
- 5609
- 5610
- 5611
- 5612
- 5613
- 4707
- 4708
- 4709
- 4710
Check the cause
Check Spool Position Sensor Values: Use a compatible Massey Ferguson diagnostic tool to read the live data from External Hydraulic Valve 1. Look for erratic, out-of-range, or missing spool position sensor values.
Inspect Wiring and Connections: Check the wiring harness connecting the Mid Mount Valve Module to External Valve 1. Look for corrosion, damaged pins, or loose connectors that could cause a connection problem.
Check Module Communication: Verify that there is no communication loss between the Dash and the Mid Mount Valve Module.
Attempt Valve Calibration: Run the tractor's hydraulic valve calibration procedure via the diagnostic interface, as the issue may simply be a calibration failure.
Repair steps
Depressurize the System
Park the tractor on a level surface, turn off the engine, and actuate the hydraulic levers/switches to relieve all hydraulic pressure from the remote valves.
Access the Valve Block
Locate the rear remote valve stack or the mid-mount valve block where External Valve 1 is housed.
Disconnect Electronics
Carefully unplug the electrical harness connector from the spool position sensor and the solenoid for Valve 1. Clean the contacts with electrical contact cleaner to rule out poor connections.
Replace the Sensor/Valve
If the sensor is deemed faulty via diagnostic tool readings, remove the retaining hardware securing the spool position sensor or the electronic valve head. Extract the faulty component.
Install New Component
Install the replacement sensor or valve section. Ensure all O-rings are lubricated with clean hydraulic fluid and properly seated to prevent leaks.
Reassemble and Reconnect
Torque the retaining bolts to OEM specifications and securely reconnect the electrical harness.
Calibrate and Clear Codes
Connect the Massey Ferguson diagnostic interface. Clear the A.12.20 DTC and perform a mandatory hydraulic valve calibration so the ECU can learn the new spool position sensor limits.
Test
Start the tractor and test the External Hydraulic Valve 1 with an implement to ensure proper flow and that the code does not return.
Parts you might need
(7)Electronic Spool Valve Control Switch
Used on 6600, 7600, and 7700 series (OEM part numbers vary by exact cab configuration, often sold as a complete switch/sensor unit).
Spool Position Sensor
External Hydraulic Valve Block
Spool Valve Front Axle Valve Block
Fits 54, 64, 66, 67, 74, 76, 86, 87 series.
Mechanical diverter/selector valve
180908M1If working on older mechanical tractors (e.g., 200, 300, 3000 series) that have been converted. Note: A.12.20 strictly applies to newer electronic systems.
Mechanical diverter/selector valve
1860100M95If working on older mechanical tractors (e.g., 200, 300, 3000 series) that have been converted. Note: A.12.20 strictly applies to newer electronic systems.
Mechanical diverter/selector valve
1696239M92If working on older mechanical tractors (e.g., 200, 300, 3000 series) that have been converted. Note: A.12.20 strictly applies to newer electronic systems.
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