Massey Ferguson A.13.28 – Mid Mount Valve Module or Tractor Control Unit (TCU): External Hydraulic Valve 1 Issue

Indicates a fault within the first external hydraulic remote valve (spool valve) circuit. The underlying condition is typically a connection problem on a hydraulic valve or an issue with the spool position sensor value.

• 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

   Use a compatible diagnostic tool or interface device to confirm the 0A.13.28 code and check for secondary codes (such as M18 or M19) which specifically point to the spool position sensor value.

2. 2

   Locate External Hydraulic Valve 1 (usually at the rear remote stack or mid-mount block) and inspect the wiring harness for chafing, breaks, or pinched wires.

3. 3

   Disconnect the electrical connector at the hydraulic valve and the spool position sensor. Check for corrosion, moisture, or loose/backed-out pins, as the system flags this primarily as a connection problem.

4. 4

   Verify the wiring continuity between the dash/TCU and the Mid Mount Valve Module to rule out a CAN bus or communication failure.

1. 1

   Power Down

   Turn off the tractor and relieve all hydraulic pressure from the system before working on the valves.

2. 2

   Clean Connections

   If the diagnostic checks revealed dirty or corroded connectors at External Hydraulic Valve 1, clean the pins with electrical contact cleaner, apply dielectric grease, and securely re-seat the connector.

3. 3

   Test the Sensor

   If the wiring is intact, test the spool position sensor for proper voltage/resistance. If the sensor is returning an out-of-range value, it must be replaced.

4. 4

   Replace Components

   If the sensor is functioning but the valve fails to actuate or communicate, remove and replace the External Hydraulic Valve 1 solenoid/assembly.

5. 5

   Clear Codes

   Reconnect a compatible diagnostic tool to clear the DTCs from the system.

6. 6

   Operational Test

   Start the tractor and actuate the remote valve to ensure the code does not return and hydraulic flow is restored.