Massey Ferguson 04.02.91 – TRANS1: Issue With Speed Sensor Values (TRANS1)

The transmission control module is receiving erratic, missing, or out-of-range rotational speed data from the transmission speed sensor.

• 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
• iT4 / T4 Models (2013-2023)

1. 1

   Visually inspect the wiring harness leading to the transmission speed sensor for chafing, breaks, or heat damage.

2. 2

   Disconnect the sensor and inspect the connector pins for corrosion, dirt, or oil/moisture ingress.

3. 3

   Measure the resistance of the sensor using a multimeter. A healthy sensor typically reads around 540 Ohms. If it reads open (infinite) or shorted, the sensor has failed internally.

1. 1

   Locate the Sensor

   The transmission speed sensor is threaded directly into the side of the transmission housing. Note: Depending on the specific tractor model and tire size, you may need to remove a rear wheel to gain adequate access to the sensor and its seized bolts.

2. 2

   Disconnect

   Unplug the electrical connector from the sensor pigtail.

3. 3

   Remove

   Unthread the faulty speed sensor from the transmission housing. Have a catch pan ready, as a small amount of transmission fluid may weep from the port.

4. 4

   Install

   Thread the new OEM speed sensor into the housing and tighten to the manufacturer's torque specification.

5. 5

   Reconnect

   Plug the electrical connector back in, ensuring the weather-tight seal clicks into place.

6. 6

   Clear Codes

   Use the tractor's onboard diagnostic interface or a dealer diagnostic tool to clear the 04.02.91 fault code so the TRANS1 module recognizes the new sensor values.