Massey Ferguson 13.01.2D – Transmission Control Unit (TCU) / TRANS1: Brake System Pressure Signal Issue Dyna VT (TRANS1)

The transmission controller has detected an abnormal or implausible signal from the brake system pressure sensor. This usually means the sensor's electrical signal voltage is out of the expected range (dropping below 1V or exceeding 5V), or the system is detecting that the hydraulic/pneumatic braking pressure is critically low (less than 4 bar / 58 psi) or excessively high.

• 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
• 8480
• 6600 Series
• 6700S Series

1. 1

   Check hydraulic fluid levels and pneumatic system pressure (ensure air pressure is above 4 bar / 58 psi)

2. 2

   Inspect the brake pressure sensor wiring harness (X135, X35, or X21) for rub points, open circuits, or shorts to ground/power

3. 3

   Test voltage at the sensor connector using a multimeter (expected range is between 1V and 5V)

4. 4

   Inspect brake pods, hydraulic lines, and the park brake hydraulic cylinder under the cab for visible leaks or pressure drops

1. 1

   Secure the Machine

   Park the tractor on a flat surface, turn off the engine, and engage the park brake (or chock the wheels if the park brake is compromised).

2. 2

   Relieve System Pressure

   Safely depressurize the hydraulic or pneumatic brake circuit before removing any components to prevent injury.

3. 3

   Repair Wiring

   If the diagnostic checks revealed a broken wire or corroded connector at the sensor, repair the harness, clean the pins, and apply dielectric grease.

4. 4

   Replace the Sensor

   If the wiring is intact but the sensor failed the multimeter test (or is physically damaged), unscrew the faulty brake pressure sensor from the valve block/line.

5. 5

   Install New Sensor

   Thread in the new OEM brake pressure sensor and tighten to the manufacturer's torque specification. Reconnect the electrical harness.

6. 6

   Bleed the System

   If hydraulic lines were opened and air entered the system, bleed the brake lines according to the service manual to restore firm pedal pressure.

7. 7

   Clear Codes

   Turn the ignition on and use a diagnostic tool to clear the 13.01.2D fault code from the TRANS1 module. Test drive to ensure the code does not return and brake pressure is stable.