Massey Ferguson 13.X.07 – TRANS1: Air Brake Solenoid Issue

The system has detected either a short circuit to +12V or an open circuit on the X339 proportional solenoid valve circuit for the pneumatic trailer brake.

• 7724S
• 5712SL
• 7722S
• 7722
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 7600 series
• 7700 series
• 8600 series

1. 1

   Locate the pneumatic trailer braking solenoid valve (Component X339) on the transmission/brake hydraulic valve block.

2. 2

   Inspect the wiring harness leading to the X339 solenoid for rubbed-through wire insulation (causing a short to power) or broken wires (causing an open circuit).

3. 3

   Disconnect the plug at the X339 solenoid and check for water ingress, corrosion, or pushed-back pins.

4. 4

   Use a multimeter to measure the resistance across the pins of the X339 solenoid coil. A reading of 'OL' (infinite resistance) indicates internal coil failure.

5. 5

   Check the continuity of the wiring from the X339 connector back to the TRANS1 module pins to rule out a harness break.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent accidental shorts while working on the transmission harness.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a broken wire or a short to +12V in the harness between TRANS1 and X339, splice and seal the damaged section using weather-resistant heat shrink connectors.

3. 3

   Replace the Solenoid

   If the wiring is intact but the X339 solenoid failed the resistance test, remove the retaining nut/clip holding the solenoid coil to the pneumatic trailer brake valve block. Slide the old coil off and install the new one.

4. 4

   Reconnect and Reassemble

   Plug the electrical connector back into the X339 solenoid, ensuring the locking tab clicks into place. Reconnect the battery.

5. 5

   Clear Codes and Test

   Use a diagnostic tool (or the tractor's onboard diagnostic menu) to clear the 13.X.07 fault code from the TRANS1 module. Start the tractor, actuate the trailer brakes, and verify the code does not return.