Case IH 111 – ATC: Cab sensor open or shorted to power

The automatic climate control system is not receiving a valid signal from the in-cab temperature sensor. The system detects that the electrical resistance/voltage is out of bounds, meaning the circuit is either completely broken (open) or the signal wire is improperly receiving voltage from another source (shorted to power).

• STX Steiger
• Magnum series (235-340 Series 4, MX Magnum, TG Series)
• Steiger series
• Puma models
• AFX series (AFX8010)

1. 1

   Locate the cab temperature sensor (often found below the operator's seat or integrated into the cab headliner/HVAC intake)

2. 2

   Visually inspect the sensor connections and the immediate wiring harness for physical damage, loose pins, or corrosion

3. 3

   Disconnect the sensor and use a multimeter to check the wiring harness back to the ATC controller for continuity (to ensure no open circuit)

4. 4

   Test the signal wire for stray voltage to ensure it is not rubbing against a live 12V wire (shorted to power)

5. 5

   Measure the resistance across the sensor's terminals (infinite resistance indicates the sensor has failed internally)

1. 1

   Power down the machine and turn off the battery disconnect switch.

2. 2

   Remove the necessary interior trim or panels to access the cab temperature sensor.

3. 3

   Disconnect the wiring harness from the sensor.

4. 4

   Repair the broken wire or insulate the shorted wire.

   Perform this if the diagnostic tests proved the wiring harness is damaged.

5. 5

   Remove the faulty sensor and install the replacement.

   Perform this if the wiring is intact but the sensor failed the resistance test.

6. 6

   Reconnect the wiring harness securely.

7. 7

   Restore battery power and turn the ignition on.

8. 8

   Clear the stored ATC 111 fault code.

   Use the machine's display monitor or an Electronic Service Tool.

9. 9

   Run the HVAC system in "Auto" mode.

   Verify that the cab temperature is reading correctly and the fault code does not return.