Massey Ferguson 13.02.0E – TRANS1: Hydraulic Trailer Brake Solenoid Issue Dyna VT

Indicates an electrical or mechanical malfunction in the solenoid responsible for actuating the hydraulic trailer brakes on tractors equipped with the continuously variable Dyna VT transmission.

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 6600 & 6700 S Series
• 6614
• 6615
• 6616
• 6713 S
• 6718 S
• 7400, 7600 & 7700 / 7700 S Series
• 7480
• 7615-7624
• 7715-7726
• 8600 & 8700 / 8700 S Series
• 8650-8690
• 8727-8740
• Newer 6S, 7S, and 8S Series
• 6S.165
• 7S.180
• 8S.205-8S.285

1. 1

   Visual Inspection: Inspect the wiring harness leading to the hydraulic trailer brake valve block (usually located near the rear axle/transmission housing). Look for chafed wires, rodent damage, or loose connections.

2. 2

   Connector Check: Disconnect the electrical connector at the trailer brake solenoid. Check for corrosion, moisture, or pushed-back pins.

3. 3

   Coil Resistance Test: Use a multimeter to measure the resistance across the solenoid coil pins. An open circuit (infinite resistance) or a short to ground indicates a burned-out coil that must be replaced.

4. 4

   Voltage Supply Test: Back-probe the connector and have an operator apply the brakes (with the engine running and safely parked). Verify that the TRANS1 module is sending the correct voltage signal to the solenoid. If voltage is missing, the issue lies in the wiring harness or the TRANS1 module itself.

5. 5

   Hydraulic Check: If the electrical circuit is sound, the valve spool inside the block may be mechanically stuck due to debris or contaminated hydraulic fluid.

1. 1

   Preparation

   Park the tractor on a level surface, engage the parking brake, lower all implements, and turn off the engine.

2. 2

   Relieve Pressure

   Actuate the brake pedals a few times to relieve any residual hydraulic pressure in the braking circuit.

3. 3

   Locate the Solenoid

   Locate the hydraulic trailer brake valve assembly at the rear of the tractor.

4. 4

   Disconnect

   Unplug the electrical harness connector from the faulty trailer brake solenoid.

5. 5

   Removal

   Remove the retaining nut or bolts securing the solenoid coil to the valve stem. If the entire cartridge valve needs replacing, use a wrench to carefully unthread the cartridge from the valve block. Have a catch pan ready for minor hydraulic fluid loss.

6. 6

   Inspection

   If replacing just the coil, ensure the valve stem is clean. If removing the cartridge, inspect the bore for scoring or debris.

7. 7

   Installation

   Install the new solenoid coil or valve assembly. Torque the retaining nut/cartridge to OEM specifications (do not overtighten, as this can distort the valve spool).

8. 8

   Reassembly

   Reconnect the electrical harness.

9. 9

   Testing

   Start the tractor, check the hydraulic fluid level, and test the trailer brakes to ensure proper operation and verify there are no leaks.

10. 10

    Clear Codes

    Use a diagnostic scan tool to clear the 13.02.0E fault code from the TRANS1 module.