Massey Ferguson 04.X.9C – TRANS2: Transmission Input Shaft Speed Sensor Open Circuit

The control module has detected a break in the electrical circuit for the transmission input shaft speed sensor. An open circuit typically indicates infinite resistance, which is caused by a severed wire, a disconnected or loose wiring harness plug, corroded connector pins, or an internal failure (broken coil) within the sensor itself.

• 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
• 5425
• 5435
• 5445
• 5455
• 5460
• 5465
• 5470
• 5475
• 5480
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 6445
• 6455
• 6460
• 6465
• 6470
• 6475
• 6480
• 6485
• 6490
• 6495
• 6497
• 6499
• 6612
• 6613
• 6614
• 6615
• 6616
• 6712S
• 6713S
• 6714S
• 6715S
• 6716S
• 6717S
• 6718S
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 8100 Series
• 8200 Series

1. 1

   Perform a visual wiring inspection by tracing the wiring harness from the sensor back to the TRANS2 module, looking for chafed wires, rodent damage, or breaks.

2. 2

   Unplug the sensor and inspect the connector pins for pushed-out pins, moisture, dirt, or corrosion.

3. 3

   Use a multimeter to measure the resistance across the sensor's pins. A reading of 'OL' (Open Loop) or infinite resistance indicates an internal failure.

4. 4

   If removing the sensor, inspect the internal tone ring through the mounting hole for damage that could cause erratic readings.

1. 1

   Prep the Machine

   Park the tractor on a level surface, engage the parking brake, and turn off the ignition. Disconnect the battery before starting any electrical work.

2. 2

   Locate the Sensor

   The transmission input shaft speed sensor is generally located on the transmission housing near the PTO shaft. Access can be tight, so ensure you have the appropriate extensions and tools.

3. 3

   Clean the Area

   Thoroughly clean the mounting area around the sensor before removal to prevent dirt, dust, or debris from falling into the transmission housing.

4. 4

   Remove the Sensor

   Disconnect the electrical wiring harness plug. Remove the retaining bolt/fastener and carefully pull the sensor out of the housing.

5. 5

   Install the New Sensor

   Insert the new sensor. Ensure it is positioned correctly relative to the tone ring (check the sensor gap if your specific model requires shimming, though most are direct-fit). Secure the retaining bolt.

6. 6

   Reconnect

   Plug the wiring harness back into the sensor until it clicks. Reconnect the tractor's battery.

7. 7

   Clear Codes

   Use a diagnostic tool to clear the 04.X.9C / 04.02.9C fault code from the TRANS2 module, then test drive the tractor to ensure smooth shifting and verify the code does not return.