Case IH 112 – ATC (Automatic Temperature Control): Cab sensor shorted to ground

The system has detected that the voltage signal from the in-cab temperature sensor is too low, indicating that the sensor's circuit is shorting directly to a ground source. When this fault is active, the climate control system may default to manual mode or limit automatic temperature regulation.

• STX Steiger
• Case IH Magnum Series (including MX Magnum, Magnum 235–340 Series 4)
• Case IH Steiger Series (e.g., 485, 500, 550)
• Case IH Puma Series
• Case IH TG Series
• Case IH Axial-Flow Combines (e.g., 7230, 8230, 9230, 8010)

1. 1

   Locate the cab temperature sensor, which is generally accessed below the operator's seat.

2. 2

   Inspect the sensor connections and the wiring harness for any visible damage, chafing, loose fit, or corrosion that could cause the circuit to short to ground.

3. 3

   Test the sensor circuit with a multimeter to confirm if the short is in the wiring harness or internal to the sensor itself.

4. 4

   If the wiring is completely intact and the sensor tests faulty, the sensor has failed. If both the wiring and sensor are good, the ATC controller itself may have a failure.

1. 1

   Turn off the machine's power.

2. 2

   Access the cab temperature sensor below the operator's seat.

3. 3

   Disconnect the sensor from the wiring harness.

4. 4

   If damage to the sensor circuit/wiring is located, repair the problem with the sensor wiring.

5. 5

   If no wiring damage is found and the sensor is internally shorted, remove the faulty cab temperature sensor and install the replacement part.

6. 6

   Reconnect the wiring harness to the new sensor.

7. 7

   Turn the machine's power back on and use the electronic service tool or the in-cab display to clear all fault codes.

8. 8

   Cycle the ATC control switch off and on.

   Verify that the digital temperature display reappears and the system no longer defaults to manual mode. Return the unit to field operation.