Massey Ferguson 04.01.40 – TRANS1: Issue With Speed Sensor Values (TRANS1)

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

• 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
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Visually inspect the transmission speed sensor's wiring harness and connector for chafing, breaks, or corrosion.

2. 2

   Unplug the sensor and measure the internal resistance using a multimeter (standard OEM speed sensors should measure approximately 540 Ohms).

3. 3

   Remove the sensor and inspect the magnetic tip for accumulated metal shavings that can distort the magnetic field.

4. 4

   Verify that the TRANS1 module is sending the correct reference voltage and that the ground circuit is intact.

1. 1

   Locate the Sensor

   Identify the transmission speed sensor on the transmission housing.

2. 2

   Clean the Area

   Thoroughly clean the area around the sensor base to prevent dirt or debris from falling into the transmission housing when the sensor is removed.

3. 3

   Disconnect

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

4. 4

   Remove the Sensor

   Unscrew the sensor from the transmission housing. Note that many of these sensors use an M20x1.5 thread and require a 24mm wrench (Turnkey size S: 24mm).

5. 5

   Install the New Sensor

   Thread the new sensor into the housing carefully to avoid cross-threading. Tighten to the manufacturer's specified torque.

6. 6

   Reconnect and Route

   Reconnect the electrical plug. Ensure the cable (which ranges from 345mm to 440mm depending on the exact part) is routed safely away from moving parts and heat sources.

7. 7

   Clear Codes

   Use a diagnostic tool or the tractor's onboard diagnostic menu to clear the 04.01.40 fault code from the TRANS1 module.

8. 8

   Test Drive

   Operate the tractor to verify that the transmission shifts correctly and the fault code does not return.