Massey Ferguson 04.00.90 – Transmission Control Unit (TRANS1): Issue With Speed Sensor Values (TRANS1)

The control module is receiving erratic, implausible, or missing data from the transmission speed sensor, which is responsible for measuring the rotational speed of the transmission shaft and transmitting it to the system.

• 7724S
• 5712SL
• 7722
• 7722S
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Inspect the transmission speed sensor's electrical cable and protective sheath for cuts, melting, or abrasion.

2. 2

   Disconnect the sensor from the main harness and check the socket/pins for dirt, moisture, or corrosion.

3. 3

   Using a multimeter, check the resistance of the sensor (standard OEM sensors typically measure around 540 Ohms). If it reads open or shorted, it has failed internally.

4. 4

   Verify continuity on the wiring harness between the sensor connector and the TRANS1 module to rule out a broken wire.

1. 1

   Locate the Sensor

   Locate the transmission speed sensor on the transmission housing. Note: Depending on the specific tractor model (e.g., MF 6499), access to the sensor may be heavily restricted and might require removing a rear tyre to safely reach the sensor port.

2. 2

   Disconnect

   Unplug the electrical connector linking the sensor to the tractor's wiring harness.

3. 3

   Remove the Sensor

   The sensor is threaded into the housing (commonly an M20x1.5 thread). Use a wrench (typically 24mm) to unscrew the faulty sensor from the transmission. Have a catch pan ready, as a small amount of transmission fluid may weep from the port.

4. 4

   Install the New Sensor

   Thread the new sensor into the housing by hand to prevent cross-threading, then tighten it to the manufacturer's torque specification.

5. 5

   Reconnect and Adapt

   Plug the electrical connector back in. If you are updating to a newer superseded sensor part number, ensure you install any required adapter harnesses.

6. 6

   Clear Codes

   Use a diagnostic tool to clear the 04.00.90 fault code from the TRANS1 module and test drive the tractor to verify the speed values are reading correctly.