Massey Ferguson 04.2.91 – TRANS: Issue With Speed Sensor Values (TRANS)

The transmission control module is receiving erratic, implausible, or missing signals from the transmission speed sensor.

• 4707
• 4708
• 4709
• 4710
• T4 (2015-2021)
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• 4600 models
• 4700 models
• 6600 series
• 6700 series
• 7600 series

1. 1

   Check the transmission speed sensor wiring harness and connectors for corrosion, loose terminals, broken wires, or water intrusion.

2. 2

   Use a diagnostic scan tool to monitor live data parameters for the transmission speed sensor while driving the tractor. Look for dropouts, spikes, or a complete lack of signal compared to actual ground speed.

3. 3

   Test the sensor's resistance (spec is often 540 +/- ohms) and verify continuity between the sensor connector and the TRANS module harness.

1. 1

   Locate the Sensor

   The transmission speed sensor is typically located on the transmission housing or on top of the hydraulic lift cover, depending on the specific model and transmission type (Dyna-4/6/VT).

2. 2

   Clean the Area

   Thoroughly clean the area around the sensor to prevent dirt or oil mist from entering the transmission housing when the sensor is removed.

3. 3

   Remove the Sensor

   Disconnect the electrical connector. Unbolt or unscrew the faulty speed sensor from the transmission housing.

4. 4

   Install the New Sensor

   Insert the new OEM speed sensor. Ensure any automotive-grade sealing O-rings are properly seated to prevent moisture ingress. Fasten to factory torque specs.

5. 5

   Reconnect and Clear Codes

   Reconnect the wiring harness. You must use a diagnostic scan tool to clear the 04.2.91 fault code from the TRANS module so the tractor's computer recognizes the new sensor and restores proper shift timing.