Case IH 13022 – INST (Instrumentation Controller): Transmission Oil Temperature sensor voltage is too high (open circuit, short to +V)

This indicates that the signal voltage returning from the transmission oil temperature sensor is out of the acceptable range on the high side, which typically points to a failed sensor, a broken/open wire, or a wire shorting to a power source.

• MX Magnum
• STX Steiger
• MX Magnum series
• TG Series
• Puma series
• Steiger tractors

1. 1

   Verify that fault code INST 13022 is active at the instrument controller.

2. 2

   Inspect the wiring harness from the instrumentation controller to the transmission oil temperature sensor for an open circuit (broken wire or disconnected plug) or a short to power (+V).

3. 3

   Disconnect the transmission oil temperature sensor and measure its internal resistance with a multimeter to check for a failed sensor.

4. 4

   Check the function of the instrumentation controller if the sensor and wiring test good, as the failure could be an internal software execution error or hardware failure within the module.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to ensure safety while testing electrical components.

2. 2

   Locate the Sensor

   Locate the transmission oil temperature sensor on the transmission housing.

3. 3

   Visual Inspection

   Disconnect the sensor's electrical connector. Inspect the pins for corrosion, moisture, or pushed-out terminals. Clean if necessary.

4. 4

   Harness Continuity Test

   Using a multimeter, test the continuity of the signal and ground wires from the sensor connector back to the Instrumentation Controller pins. Repair any broken wires or shorts to power.

5. 5

   Replace the Sensor

   If the wiring harness is intact but the sensor failed the resistance test (or reads as an open circuit internally), unthread the old sensor from the transmission housing. Be prepared to catch a small amount of transmission fluid. Thread in the new OEM sensor and tighten to specification.

6. 6

   Reassemble and Clear Codes

   Reconnect the electrical harness, reconnect the battery, and power on the tractor. Clear the stored fault codes from the INST controller and run the machine to verify that the transmission temperature registers correctly and the code does not return.