Massey Ferguson 04.03.85 – TRANS1: Issue With Signal From Transmission Mounted Engine Speed Sensor (TRANS) / Issue With Speed Sensor Values (TRANS1)

The transmission control system is receiving an irregular, intermittent, or missing signal from the speed sensor mounted on the transmission, which monitors the input/engine speed to the gearbox.

• 7724S
• 5712SL
• 7722S
• 7722
• 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
• 6445
• 6455
• 6460
• 6465
• 6470
• 6475
• 6480
• 6485
• 6490
• 6495
• 6497
• 6499
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Connect the tractor to the Massey Ferguson Wintest diagnostic software. Check the active and requested values for the transmission speed sensor.

2. 2

   If Wintest shows incorrect values, no value, or an intermittent signal, test the inductive sensor using a multimeter. Disconnect the sensor and measure the resistance of the sensor coil when the tractor is stationary. If the resistance is out of specification (or shows an open/short circuit), the sensor is faulty.

3. 3

   Inspect the wiring harness and connectors between the transmission speed sensor and the TRANS1 control module. Look for chafed wires, corrosion in the connector pins, or loose connections that could cause signal dropouts.

1. 1

   Preparation

   Park the tractor on a level surface, engage the parking brake, and turn off the engine.

2. 2

   Locate the Sensor

   Locate the transmission-mounted engine speed sensor on the side of the gearbox housing. Depending on the tractor model (e.g., 6499), this may require removing a rear tire to gain adequate access to the sensor.

3. 3

   Drain Fluid (If Necessary)

   Depending on the sensor's exact mounting height on your specific transmission, you may need to partially drain the transmission oil to prevent fluid loss when the sensor is removed.

4. 4

   Remove the Sensor

   Disconnect the electrical harness from the sensor. Unthread or unbolt the faulty speed sensor from the transmission housing.

5. 5

   Install the New Sensor

   Thread the new sensor into the housing (ensure any sealing rings or O-rings are in place).

6. 6

   Reconnect and Reassemble

   Reconnect the electrical harness. Refill any drained transmission fluid. Reinstall the tire if it was removed.

7. 7

   Clear Codes

   Use the diagnostic tool to clear the 04.03.85 fault code and test drive the tractor to ensure the transmission shifts correctly and the speed values register in the system.