Massey Ferguson T254 – TRANS2: Transmission Input Shaft Speed Sensor Open Circuit

The transmission controller is not receiving a valid signal from the inductive speed sensor that monitors the rotational speed of the transmission input shaft. The system has detected an open circuit, which typically points to a broken wire, a disconnected plug, or an internal failure within the sensor itself.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 6400 Series
• 6600 Series
• 6700 Series
• 7700 Series

1. 1

   Inspect the wiring harness leading to the transmission input shaft speed sensor for physical damage, chafing, or broken wires.

2. 2

   Disconnect the sensor and check for corrosion, moisture, or pushed-back pins in the connector.

3. 3

   Use a multimeter to check the sensor for an internal open circuit. Additionally, test the wiring harness for continuity between the sensor connector and the Autotronic 5 (TRANS2) ECU pins to rule out a broken wire in the harness.

4. 4

   Look for related code T255 (Transmission Input Shaft Speed Sensor Calibration Fault), which frequently accompanies this sensor's failure.

1. 1

   Locate the sensor

   Locate the transmission input shaft speed sensor on the exterior of the transmission housing.

2. 2

   Disconnect sensor

   Carefully unplug the electrical connector from the sensor.

3. 3

   Remove sensor

   Remove the retaining bolt holding the sensor in place. Pull the sensor straight out of the transmission housing. Have a catch pan ready, as a small amount of transmission/hydraulic fluid may weep from the port.

4. 4

   Install new sensor

   Lubricate the O-ring on the new sensor with clean transmission fluid to prevent tearing. Insert the new sensor into the port and secure it with the retaining bolt.

5. 5

   Reconnect wiring

   Plug the electrical connector back in, ensuring the locking tab clicks into place.

6. 6

   Clear code and test

   Clear the T254 fault code from the Autotronic 5 module using a diagnostic tool or the tractor's dash interface. Start the tractor and perform a test drive to verify that the transmission shifts smoothly and the code does not return.