Massey Ferguson 04.01.92 – TRANS1: Issue With Speed Sensor Values (TRANS1)

The transmission control system is receiving erratic, implausible, or missing signals from one of the transmission speed sensors. The controller relies on these values to manage clutch engagement, shifting (e.g., Dyna-4, Dyna-6, or Dyna-VT transmissions), and overall tractor speed calculation.

• 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

   Inspect the wiring harness leading to the transmission speed sensors for chafing, breaks, or melted insulation.

2. 2

   Disconnect the sensor and check the pins for corrosion, moisture, or poor terminal tension.

3. 3

   Perform a sensor resistance test using a multimeter (should read approximately 540 Ohms +/-). An open circuit or dead short indicates a failed internal coil.

4. 4

   Remove the sensor and inspect the magnetic pickup tip for metallic shavings or sludge that could distort the magnetic field. Clean and re-test.

5. 5

   Verify that the transmission/hydraulic oil is at the correct level and the filters are clean, as low fluid can cause aeration or mechanical slipping.

1. 1

   Locate the Sensor

   Identify the specific transmission speed sensor throwing the code (input, intermediate, or output shaft speed sensor) on the side of the transmission housing.

2. 2

   Clean the Area

   Thoroughly clean the transmission casing around the sensor to prevent dirt from falling into the gearbox when the sensor is removed.

3. 3

   Disconnect

   Unplug the electrical connector from the sensor harness.

4. 4

   Remove the Sensor

   Unscrew the sensor from the transmission housing. Have a shop rag ready, as a small amount of transmission fluid may weep from the port.

5. 5

   Install the New Sensor

   Thread the new OEM speed sensor into the housing. Tighten it to the manufacturer's specified torque (do not overtighten, as the sensor body can crack).

6. 6

   Reconnect

   Plug the electrical connector back in, ensuring the locking tab clicks into place. Secure any loose wiring with zip ties to prevent future chafing.

7. 7

   Clear Codes

   Turn the key to the ON position and use a diagnostic tool (or the tractor's onboard dash diagnostic menu) to clear the inactive 04.01.92 fault code.

8. 8

   Test Drive

   Operate the tractor through all gears/ranges to verify that the transmission shifts smoothly and the fault code does not return.