Case IH 16116 – ATC (Automatic Temperature Controller): Evaporator temperature sensor is shorted to ground

The control module is receiving a voltage signal from the A/C evaporator temperature sensor that is lower than the acceptable range, indicating a direct short circuit to ground either within the sensor itself or in its wiring harness.

• Puma/Mid Range Magnum
• Maxxum
• Case IH Magnum Series
• Case IH Puma Series
• Case IH Steiger Series
• Case IH TG Series

1. 1

   Verify the active fault code 16116 (or ATC 116) in the diagnostic menu on the Universal Display or A-post monitor

2. 2

   Inspect the wiring harness from the ATC module to the evaporator temperature sensor for chafed insulation, pinched wires, or melted areas touching the chassis

3. 3

   Disconnect the evaporator temperature sensor and measure resistance across its terminals (near zero indicates an internal short)

4. 4

   With the sensor unplugged, check for continuity between the harness signal wire and chassis ground to test for a shorted harness

5. 5

   Ensure all cab and battery ground connections are clean and tight

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical damage.

2. 2

   Access the HVAC Plenum

   Depending on the specific tractor model, the HVAC unit is typically located either under the operator's seat or in the cab roof. Remove the necessary access panels or raise the seat to expose the HVAC housing and the electrical distribution area.

3. 3

   Locate the Sensor

   Find the evaporator temperature sensor, which is inserted into the evaporator core fins or the plenum chamber.

4. 4

   Remove the Faulty Sensor

   Unplug the electrical connector. Carefully pull the sensor probe out of its mounting location.

5. 5

   Install the New Sensor

   Insert the replacement evaporator temperature sensor into the exact same location, ensuring it is properly seated so it can accurately read the temperature of the evaporator core to prevent freezing.

6. 6

   Reconnect and Reassemble

   Plug the electrical connector back in, ensuring the wiring is routed safely away from sharp edges. Reinstall the access panels and the operator's seat.

7. 7

   Clear Codes and Test

   Reconnect the battery, turn on the ignition, and clear the fault codes via the diagnostic display. Run the A/C system to verify that the ATC operates correctly and the 16116 code does not return.