Massey Ferguson 13.X.0B – TRANS1: Hydraulic Trailer Brake Solenoid Issue

Fault with the X39 Trailer Braking Safety Solenoid Valve, indicating that the circuit is experiencing an open circuit or a short circuit to +12V.

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 8400 Series
• 8600 Series
• 8670
• 8690
• 8700 Series
• 8700S Series

1. 1

   Visually inspect the X39 Trailer Braking Safety Solenoid Valve on the transmission hydraulic block, checking the wiring harness and electrical connector for corrosion, frayed wires, or loose pins.

2. 2

   Test the circuit using a multimeter between the TRANS1 controller and the X39 solenoid to confirm if there is a physical open circuit or a short to +12V.

3. 3

   Measure the resistance across the pins of the X39 solenoid coil (an infinite reading indicates a burned-out coil/open circuit, while zero indicates an internal short).

4. 4

   Verify the tractor's hydraulic trailer brake pressure is set correctly, as improper settings can cause system strain.

1. 1

   Park the tractor on a level surface, engage the parking brake (ParkLock), and turn off the engine.

   Ensure the tractor is safely parked before beginning repairs.

2. 2

   Relieve any residual hydraulic pressure in the system by operating the brake pedals a few times.

   This prevents pressurized fluid from escaping during disassembly.

3. 3

   Locate the X39 Trailer Braking Safety Solenoid Valve on the exterior transmission/solenoid valve harness connection block.

   Identify the correct valve for replacement.

4. 4

   Disconnect the electrical harness connector from the X39 solenoid.

   Free the solenoid from the tractor's wiring harness.

5. 5

   Remove the retaining nut at the end of the solenoid stem.

   This nut secures the coil to the valve cartridge.

6. 6

   Slide the faulty solenoid coil off the valve cartridge.

   Note: If the valve cartridge itself is physically stuck or damaged, unscrew the cartridge from the hydraulic block. Be prepared to catch a small amount of hydraulic oil.

7. 7

   Slide the new solenoid coil onto the valve stem and secure it with the retaining nut, tightening to the manufacturer's specified torque.

   Ensure the new coil is properly seated and secured.

8. 8

   Reconnect the electrical harness connector.

   Restore electrical connection to the new solenoid.

9. 9

   Start the tractor and check for any hydraulic leaks around the valve block.

   Verify the integrity of the hydraulic seal if the cartridge was removed.

10. 10

    Connect a diagnostic tool to the tractor's OBD port and clear the 13.X.0B fault code from the TRANS1 module.

    Clear the logged fault from the transmission controller.

11. 11

    Test the hydraulic trailer brakes to ensure proper engagement and release.

    Confirm the repair has restored full functionality to the trailer braking system.