Massey Ferguson 04.02.9C – TRANS2: Transmission Input Shaft Speed Sensor Open Circuit

The transmission controller is not detecting a complete electrical circuit to the input shaft speed sensor. This typically means a wire is broken, a connector is unplugged, there is severe corrosion blocking the signal, or the sensor's internal coil has failed.

• 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

   Locate the sensor near the PTO shaft/transmission housing and visually inspect the wiring harness for severed wires, rodent damage, or a disconnected plug.

2. 2

   Unplug the sensor and check the connector pins for corrosion, moisture, or pushed-out terminals.

3. 3

   Use a multimeter to measure the resistance across the sensor's pins. If it reads 'OL' (Open Loop) or infinite resistance, the sensor has failed internally.

4. 4

   If the sensor tests good, check the wiring harness for continuity between the sensor connector and the TRANS2 module pins.

1. 1

   Disconnect Power

   Disconnect the tractor's battery before beginning electrical work.

2. 2

   Clean the Area

   Thoroughly clean the mounting area around the sensor on the transmission housing to prevent dirt and debris from falling into the transmission.

3. 3

   Remove the Sensor

   Unbolt and carefully extract the old sensor.

4. 4

   Inspect the Tone Ring

   Look through the sensor mounting hole to verify the condition of the internal tone ring (the geared wheel the sensor reads). Ensure it is not damaged or covered in excessive metallic debris.

5. 5

   Install the New Sensor

   Insert the new sensor. Note that inductive speed sensors must be positioned correctly relative to the tone ring. Ensure the sensor gap is correct according to your specific model's service manual.

6. 6

   Reassembly

   Reconnect the wiring harness securely and reconnect the battery.

7. 7

   Clear Codes

   Clear the 04.02.9C fault code from the TRANS2 module and test drive the tractor to ensure erratic shifting is resolved and the code does not return.