Case IH 16112 – Automatic Temperature Controller (ATC): Cab sensor shorted to ground

The signal voltage from the cab's interior temperature sensor has dropped to zero. Because the sensor circuit is shorted to ground, the climate control system cannot accurately read the ambient temperature inside the cabin, which typically causes the automatic climate control to malfunction or blow air at incorrect temperatures.

• Puma/Mid Range Magnum
• Maxxum
• Case IH Puma Series: 125, 140, 165, 180, 195, 210, 225 CVX
• Case IH Magnum Series: 215, 235, 245, 275, 305, 340 (Series 4)
• Case IH Steiger & Quadtrac Series: 350, 400, 450, 500, 550, 600
• Case IH Combines: Axial-Flow series (e.g., 7230)

1. 1

   Visually inspect the cab temperature sensor and its connector for physical damage, moisture, or corrosion.

2. 2

   Perform a sensor resistance test using a multimeter; a reading of 0 ohms indicates an internal dead short and a failed sensor.

3. 3

   Test the wiring harness signal wire for continuity to ground with the sensor disconnected.

4. 4

   Trace and inspect the wiring harness from the cab sensor to the ATC module for pinched, chafed, or melted wires.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical spikes during the repair.

2. 2

   Access the Sensor

   Remove the necessary cab interior trim panels or headliner sections to access the cab temperature sensor and its wiring harness.

3. 3

   Address the Short

   If the sensor is faulty: Unclip or unscrew the old sensor from its mounting bracket. Plug the electrical connector into the new OEM replacement sensor and snap it into place. If the wiring is faulty: Locate the chafed or pinched section of the wire. Cut out the damaged section, splice in a new piece of wire using solder and heat-shrink tubing, and secure the harness away from sharp metal edges.

4. 4

   Reassembly

   Reinstall all interior cab trim panels and headliner components.

5. 5

   Clear Codes & Test

   Reconnect the battery and turn the ignition on. Use the tractor's diagnostic menu or an Electronic Service Tool (EST) to clear the inactive 16112 / ATC 112 fault code. Run the A/C system in 'Auto' mode to verify that the ATC module is properly regulating the cab temperature.