Massey Ferguson P54 – TRANS1: Brake System Pressure Not Dropped When Brake Applied

Indicates a discrepancy between the physical status of the brake pedals and the hydraulic pressure in the braking system. The transmission controller detects that when the brake pedal is applied (or released), the hydraulic pressure reading from the braking pressure sensor does not drop as expected.

• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• Interim Tier 4 (2012-2015)
• MF 7600 Series
• MF 8600 Series
• MF 6700 S Series

1. 1

   Mechanical Inspection: Check the physical brake pedals to ensure they are not mechanically binding, sticking, or failing to return fully to their resting positions.

2. 2

   Sensor Data Verification: Use a diagnostic tool to monitor live data from the Left-hand brake pedal sensor (X66), Right-hand brake pedal sensor (X67), and the Braking pressure sensor (X135).

3. 3

   Voltage & Pressure Checks: Verify the voltage of the braking pressure sensor (X135). The normal operating range is between 1V and 5V. If the voltage is outside this range, or if the pressure reads artificially high (e.g., greater than 230 bar / 3336 psi), the sensor is likely faulty.

4. 4

   Wiring Harness Inspection: Inspect the wiring and connectors for sensors X66, X67, and X135. Look for data transfer interruptions, short circuits to earth, or damaged pins that could cause a false reading to the TRANS1 module.

1. 1

   Secure the Tractor

   Park the tractor on level ground, turn off the engine, and engage the ParkLock/parking brake.

2. 2

   Access the Sensors

   Locate the brake pedal sensors (X66 and X67) at the base of the brake pedals in the cab, and locate the braking pressure sensor (X135) on the brake valve block.

3. 3

   Test Electrical Connections

   Disconnect the harnesses from the sensors and use a multimeter to check for continuity and proper ground. Clean any corrosion from the connector pins.

4. 4

   Replace Faulty Component

   If the diagnostic tool shows the brake pedal sensors are functioning but the pressure sensor is stuck at a high value, depressurize the hydraulic system and replace the braking pressure sensor. If the pedal sensors are failing to register movement, replace the faulty pedal switch/sensor.

5. 5

   Reassemble and Bleed

   If the hydraulic pressure sensor was replaced, ensure the system is properly bled according to the service manual to remove any trapped air.

6. 6

   Clear Codes and Calibrate

   Reconnect the diagnostic tool, clear the P54 fault code from the TRANS1 module, and perform a test drive to ensure the brake pressure drops correctly upon application and the code does not return.