Massey Ferguson T126 – Transmission Controller (TRANS1) / Autotronic 5: Issue With Speed Sensor Values

The transmission controller detects that the signal from the theoretical forward travel speed sensor (X482) is missing, out of range, or implausible depending on the transmission range currently engaged.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720

1. 1

   Perform diagnostic tests on the sensors using the Massey Ferguson Wintest diagnostic software before replacing any parts.

2. 2

   Inspect the wiring harness and connectors for open circuits, short circuits to ground, or short circuits to +12V.

3. 3

   Check for concurrent codes related to the intermediate speed sensor (X483), as a failure there can trigger implausibility codes for the forward speed sensor.

1. 1

   Locate the Sensor

   Locate the theoretical forward speed sensor (X482) on the transmission housing.

2. 2

   Disconnect and Inspect

   Unplug the electrical connector. Check for oil intrusion, dirt, or corroded pins.

3. 3

   Remove the Sensor

   If Wintest software and wiring checks confirm the sensor has failed internally, remove the retaining bolt and carefully pull the sensor from the transmission housing.

4. 4

   Install the New Sensor

   Lubricate the O-ring on the new genuine AGCO/Massey Ferguson sensor and seat it into the housing. Secure it with the retaining bolt.

5. 5

   Reconnect

   Plug the wiring harness back into the sensor, ensuring the weather-tight seal clicks into place.

6. 6

   Clear Codes

   Connect your diagnostic tool and clear the T126 fault code from the TRANS1 (Autotronic 5) module.

7. 7

   Test Drive

   Operate the tractor through its various ranges to ensure the transmission shifts smoothly and the code does not return.