Massey Ferguson 14.02.0B – TRANS1: High Pressure Brake System Pressure Not Dropping DYNA 6 (TRANS1)

The system is detecting that the hydraulic or pneumatic pressure in the high-pressure brake circuit (which controls the trailer brakes or the tractor's handbrake/ParkLock system) is failing to decrease to the expected baseline when the brake pedal or handbrake is released. This can be caused by a mechanical issue (a stuck brake control valve holding pressure) or an electrical issue (a faulty pressure sensor sending an inaccurate high-voltage signal).

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 5611
• 5612
• 5613
• 5709
• 5710
• 5711
• 5712
• 5713
• 6465
• 6475
• 6480
• 6485
• 6490
• 6495
• 6613
• 6614
• 6615
• 6616
• 6713
• 6714
• 6715
• 6716
• 6718
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 8670
• 8680
• 8690
• 8727
• 8730
• 8732
• 8735

1. 1

   Verify the Pressure Mechanically: Attach a manual digital pressure indicator to the brake pressure tap (located on the brake manifold mounted to the bevel gear case at the rear of the machine). Actuate and release the brakes to see if the physical oil/air pressure actually drops.

2. 2

   Inspect Couplers (If Pneumatic): If the tractor is hooked up to an implement, check the condition of the air connection couplers and the implement's braking system, as a blockage here can prevent pressure from venting.

3. 3

   Test the Sensor Wiring: Locate the High Pressure Brake Sensor / Handbrake Pressure Sensor. Inspect the wiring harness and connector for corrosion, pinched wires, or a short to voltage (which would cause the controller to read a falsely high pressure).

4. 4

   Test the Sensor: Use a multimeter to check the signal voltage from the sensor while the brake is released. If the physical pressure is verified to be zero but the sensor is still outputting a high-pressure voltage signal, the sensor is internally shorted or stuck.

1. 1

   Relieve System Pressure

   Park the tractor on a smooth, horizontal surface. Lower all implements, shut off the engine, and turn the key to the ON position. Pump the brake pedals and move the implement control levers multiple times to release any residual hydraulic/pneumatic pressure in the system.

2. 2

   Replace the Faulty Component

   If the sensor failed the diagnostic test: Disconnect the electrical harness from the brake pressure sensor. Unthread the old sensor from the brake valve block. Install the new OEM sensor and tighten to the manufacturer's torque specification. Reconnect the harness. If the mechanical pressure was actually failing to drop: Remove and clean or replace the brake control valve/solenoid, as the internal spool may be sticking and failing to return fluid to the sump.

3. 3

   Bleed the Brakes

   If hydraulic lines were opened, bleed the brake system to remove any air pockets.

4. 4

   Clear Codes and Calibrate

   Enter the tractor's diagnostic interface via the dashboard or a dealer diagnostic tool. Clear the 14.02.0B fault code. It is highly recommended to perform a calibration of the Dyna-6 transmission and electrohydraulic block after replacing transmission/brake sensors.