Massey Ferguson 04.00.89 – TRANS: Transmission Oil Temperature Signal Issue

The control module is receiving an irregular, missing, or out-of-range electrical signal from the transmission oil temperature sensor. This indicates an electrical fault in the sensor circuit, such as an open circuit, a short to ground, a short to power, or a completely failed sensor element.

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Inspect the wiring harness and the electrical connector at the transmission oil temperature sensor (sensor X19) for broken wires, corrosion, or backed-out pins.

2. 2

   Use a multimeter to check for continuity between the sensor connector and the TRANS module harness. Test for any shorts to ground or shorts to power in the signal wire.

3. 3

   Measure the resistance across the terminals of the temperature sensor. If the sensor reads 'open' (infinite resistance) or is completely shorted, the sensor itself has failed internally.

4. 4

   Use an infrared (IR) temperature gun on the transmission housing to verify the actual temperature of the transmission fluid to ensure the transmission isn't experiencing extreme temperature fluctuations.

5. 5

   Check the transmission/hydraulic oil level and condition. Low or highly contaminated fluid can sometimes cause erratic sensor readings.

1. 1

   Park and prepare the tractor

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

2. 2

   Locate the sensor

   Locate the transmission oil temperature sensor on the transmission housing (typically threaded into the side of the transmission case or near the hydraulic filter block).

3. 3

   Clean the area

   Thoroughly clean the area around the sensor to prevent dirt and debris from entering the transmission housing.

4. 4

   Disconnect the harness

   Disconnect the electrical harness connector from the sensor.

5. 5

   Prepare for fluid loss

   Place a clean drain pan underneath the sensor location to catch any transmission fluid that escapes.

6. 6

   Remove the faulty sensor

   Use a wrench or deep socket to unthread and remove the faulty temperature sensor.

7. 7

   Install the new sensor

   Install the new transmission oil temperature sensor. Ensure any required O-rings or sealing washers are in place. Tighten to the OEM torque specification.

8. 8

   Reconnect the harness

   Reconnect the electrical harness connector, ensuring it clicks securely into place.

9. 9

   Check and top off fluid

   Check the transmission fluid level via the sight glass or dipstick and top off any fluid lost during the swap.

10. 10

    Clear code and test drive

    Turn on the tractor, clear the 04.00.89 fault code using a diagnostic tool or the armrest terminal, and test drive the machine to ensure the code does not return.