Case IH 13021 – INST: Transmission Oil Temperature sensor voltage is too low (short to ground)

The system is receiving a signal from the sensor that is out of the acceptable range on the low side, which typically means the sensor has failed internally or the wiring harness is shorting out against the chassis.

• MX Magnum
• STX Steiger
• TG Series
• Puma
• Steiger
• Maxxum
• Optum
• JX
• MXM series

1. 1

   Check the transmission oil temperature sensor's resistance with a multimeter to see if it is out of specification.

2. 2

   Inspect and test the wiring harness running from the instrumentation controller to the transmission oil temperature sensor for a short to ground.

3. 3

   Check the function of the instrument controller to verify if the sensor fails within the instrument controller's logic (triggering INST 13021 or 13022).

1. 1

   Locate and Disconnect

   Locate the transmission oil temperature sensor on the transmission housing and disconnect its electrical connector.

2. 2

   Test the Sensor

   Using a multimeter, measure the resistance across the sensor's terminals. If the sensor reads as a dead short or is completely out of the specified resistance range, the sensor has failed and must be replaced.

3. 3

   Test the Wiring

   If the sensor tests good, use the multimeter to check the wiring harness between the sensor connector and the instrument controller. Test for continuity to ground on the signal wire. If a short to ground is found, trace the harness to find the chafed or damaged wire and repair or replace the harness.

4. 4

   Check the Controller

   If both the sensor and the wiring harness are in good working order, the issue may be a hardware failure or software execution error within the instrument controller itself. In this case, the controller may need to be reflashed or replaced.