Case IH 2605 (5913.18) - DEC – Drivetrain Electronic Controller (DEC) / Transmission Control Unit (TCU) / Instrument Controller (INST): Transmission Oil Temperature Sensor - temp too low.

The controller is receiving a voltage signal from the transmission oil temperature sensor that falls below the normal operating threshold. This is most commonly caused by a short to ground in the sensor circuit, an open circuit, a failed internal thermistor in the sensor, or (in specific calibration scenarios) the transmission fluid genuinely being too cold to proceed with operations like transmission calibration.

• VESTRUM CVX
• Steiger Series (350 to 600)
• Magnum Series (235 - 340)
• MX Series (MX100, MX110, MX120, MX135)
• TG Series
• Farmall Series (105C, 105U)
• MXU Series (MXU110)

1. 1

   Inspect the transmission oil temperature sensor and its wiring harness for visible damage, chafing, or disconnected wires.

2. 2

   Disconnect the sensor and check for corrosion, moisture, or bent pins in the connector.

3. 3

   Measure the resistance of the temperature sensor with a multimeter. Compare the reading to the OEM specifications for the ambient temperature to determine if the sensor has failed internally.

4. 4

   Check for continuity and ensure there is no short to ground or short to power in the wiring between the sensor and the controller (DEC/TCU/INST).

5. 5

   If the code appears during a calibration procedure, ensure the transmission fluid has been warmed up to at least 140°F (60°C).

1. 1

   Park and prepare machine

   Park the tractor on a level surface, turn off the engine, and engage the parking brake. Allow the transmission to cool if it is hot.

2. 2

   Locate sensor

   Locate the transmission oil temperature sensor on the transmission housing (refer to your specific model's service manual for the exact port location).

3. 3

   Clean area

   Clean the area around the sensor thoroughly to prevent dirt or debris from entering the transmission.

4. 4

   Disconnect harness

   Disconnect the electrical wiring harness from the sensor.

5. 5

   Prepare for fluid leak

   Place a clean drain pan under the sensor area to catch any transmission fluid that may leak out during removal.

6. 6

   Remove sensor

   Using the appropriate wrench or deep socket, unscrew and remove the faulty temperature sensor.

7. 7

   Install new sensor

   Install the new OEM transmission oil temperature sensor. (Note: Some sensors require a thread sealant; check the new part to see if it is pre-applied). Tighten to the OEM specified torque.

8. 8

   Reconnect harness

   Reconnect the electrical wiring harness to the new sensor, ensuring it clicks into place.

9. 9

   Check fluid level

   Check the transmission fluid level and top off any fluid that was lost during the replacement.

10. 10

    Clear codes and verify

    Turn on the tractor, clear the fault codes using an electronic service tool or the in-cab diagnostic menu, and run the machine to verify the code does not return.