Massey Ferguson 04.03.89 – TRANS: Transmission Oil Temperature Signal Issue (TRANS)

The control module is receiving an invalid, out-of-range, or missing electrical signal from the transmission hydraulic oil temperature sensor. This can be caused by a failed sensor, a wiring issue (short to ground or open circuit), or an actual extreme temperature condition (such as overheating due to a blocked cooler or low fluid).

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 7700 Series

1. 1

   Verify actual transmission temperature using an infrared (IR) temperature gun on the casing to confirm if the transmission is actually overheating or if the sensor is sending a false reading

2. 2

   Inspect the transmission/hydraulic oil cooler and radiator for blockages caused by dust and debris

3. 3

   Check transmission/hydraulic fluid levels and verify that the hydraulic filters are not clogged

4. 4

   Inspect the transmission oil temperature sensor wiring harness and electrical connector for corrosion, broken wires, or loose pins

5. 5

   Test the sensor with a multimeter for correct voltage/resistance to identify a short to ground (voltage too low) or an open circuit (voltage too high)

1. 1

   Clean the Cooling System

   If the transmission is genuinely overheating, thoroughly wash/blow out the transmission oil cooler and radiator fins from front to back.

2. 2

   Prep for Sensor Replacement

   Park the tractor on a level surface, turn off the engine, and allow the transmission to cool. Place a drain pan under the sensor location to catch any fluid loss.

3. 3

   Remove the Faulty Sensor

   Disconnect the electrical harness from the transmission oil temperature sensor. Unscrew the sensor from the transmission casing.

4. 4

   Install the New Sensor

   Thread the new temperature sensor into the casing (ensure any required O-rings or thread sealants are in place) and tighten to the manufacturer's torque specification.

5. 5

   Reconnect and Refill

   Plug the electrical connector back into the sensor. Check the transmission fluid dipstick/sight glass and top off the hydraulic/transmission fluid to replace any that was lost during the swap.

6. 6

   Clear Codes

   Use a diagnostic tool to clear the 04.03.89 DTC from the TRANS module, then test drive the tractor under load to ensure the code does not return.