Massey Ferguson 4.00.B8 – TRANS1: Issue With Intermediate Speed Sensor Values

Triggered when the transmission controller detects a severe discrepancy between vehicle sensors. Specifically, the system logs this error when the intermediate speed sensor registers 'no value' (0 km/h or 0 rpm) while the actual forward travel speed sensor or engine speed sensor indicates that the tractor is currently moving.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 5400
• 6400
• 7600

1. 1

   Connect the tractor to the Massey Ferguson Wintest diagnostic software and monitor the active values of the intermediate speed sensor (TR25) in RPM while driving to compare against engine and theoretical forward speed.

2. 2

   Disconnect the sensor and measure its internal resistance using a multimeter (a healthy sensor reads approximately 540 Ohms; infinite or 0 Ohms confirms a dead sensor).

3. 3

   Inspect the wiring harness for damage, open circuits, or short circuits to +12V or 0V at the sensor connector (TR25.1 / TR25.2) and the Autotronic 5 controller pins (CAB50, CAB162).

4. 4

   Verify the forward speed sensor and engine speed sensor are functioning correctly, as the TRANS1 module uses them as the baseline to flag the TR25 sensor as faulty.

1. 1

   Park the tractor

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

2. 2

   Locate the sensor

   Locate the intermediate speed sensor (TR25 / X483) on the transmission housing.

3. 3

   Disconnect the sensor

   Disconnect the electrical connector from the sensor's pigtail cable.

4. 4

   Clean the area

   Thoroughly clean the area around the sensor base to prevent dirt from falling into the transmission housing.

5. 5

   Remove the sensor

   Unscrew the sensor from the transmission housing. (Note: It typically features an M20x1.5 or M26x1.5 threaded body depending on the exact transmission).

6. 6

   Install the new sensor

   Lubricate the O-ring/sealing ring on the new genuine Massey Ferguson sensor and thread it into the housing. Tighten to OEM torque specifications.

7. 7

   Reconnect the sensor

   Route the sensor cable safely away from moving parts and heat sources, and reconnect the electrical plug.

8. 8

   Clear the fault code

   Clear the stored 4.00.B8 fault code using the diagnostic tool.

9. 9

   Perform calibration

   Because several mechanical and electrical components are involved in the PowerShuttle/Dyna operation, it may be necessary to carry out a clutch/transmission calibration after replacing the sensor.

10. 10

    Test drive

    Perform a test drive to verify that the intermediate speed sensor now registers > 0 km/h when the tractor is moving.