Case IH 116 – ATC (Automatic Temperature Control): Evaporator sensor is shorted to ground

The control module is detecting a voltage near zero on the evaporator temperature sensor circuit. This is typically caused by the sensor failing internally (shorting out) or the signal wire in the harness chafing and making direct contact with the machine's chassis/ground.

• STX Steiger
• Case IH Magnum MX/TG Series
• Case IH Magnum Series 4 235-340
• Case IH Magnum MX285
• Case IH Steiger 380
• Case IH Steiger 430
• Case IH Steiger 480
• Case IH Steiger 485
• Case IH Steiger 530
• Case IH Puma series
• Case IH Axial-Flow Combine 2144
• Case IH Axial-Flow Combine 2166
• Case IH Axial-Flow Combine 2344
• Case IH Axial-Flow Combine 2366
• Case IH Axial-Flow Combine 2377
• Case IH Axial-Flow Combine 2388
• Case IH Axial-Flow Combine 2577
• Case IH Axial-Flow Combine 2588
• Case IH Axial-Flow Combine 5088
• Case IH Axial-Flow Combine 6088
• Case IH Axial-Flow Combine 7088
• Case IH Cotton Picker CPX420
• Case IH Cotton Picker CPX610
• Case IH Cotton Picker CPX620
• Case IH Cotton Picker 2155
• Case IH Cotton Picker 2555

1. 1

   Disconnect the evaporator temperature sensor and measure resistance across its terminals; a reading near 0 ohms indicates an internal short.

2. 2

   Check the wiring harness between the sensor connector and the ATC module for chafing, probing the signal wire for continuity to ground.

3. 3

   Verify all battery and cab ground connections have less than 1 ohm resistance from the battery post to the frame.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the Sensor

   Locate the evaporator temperature sensor in the HVAC plenum. On many tractors, this is under the cab seat, requiring you to raise or remove the operator seat to access the divider where the sensor is mounted.

3. 3

   Remove the Faulty Sensor

   Disconnect the electrical pigtail from the sensor. Carefully pull or unclip the sensor probe from the evaporator core housing.

4. 4

   Install the New Sensor

   Insert the replacement sensor into the exact same position in the evaporator fins/housing to ensure accurate temperature readings.

5. 5

   Reassembly

   Reconnect the electrical harness. Reinstall the seat and any access panels that were removed.

6. 6

   Clear Codes and Test

   Reconnect the battery, turn the key on, and use the ATC diagnostic menu to clear the fault codes. Run the A/C system on 'Auto' to verify that the output temperature regulates correctly and Code 116 does not return.