Case IH 14019 – ICU (Instrumentation Control Unit): ATC Off Line

This indicates a CAN bus communication problem where the Automatic Temperature Control (ATC) module has disconnected from the machine's network. The main controller is no longer receiving valid CAN messages from the ATC system, which regulates the cab's HVAC system (fan speed, air distribution, and temperature settings).

• Magnum
• Steiger T4B
• Case IH Magnum Tractors: MX series (MX210, MX230, MX255, MX285), standard Magnums (215, 225, 235, 245, 250, 260, 275, 280, 290, 310, 315, 335, 340 Series 4)
• Case IH Steiger / STX Tractors: 350 to 600 HP models
• Case IH Combines: 2588, 5088, 5130, 6088, 7088, 7120, 7130, 8010, 8120, 8230, 9010, 9240

1. 1

   Verify Power and Ground: Check the fuses and relays supplying power to the ATC module. Use a multimeter to ensure the module is receiving 12V power and has a solid ground connection.

2. 2

   Inspect the Harness and Connectors: Locate the ATC module (typically located inside the cab console or headliner near the HVAC controls). Disconnect the harness and inspect the pins for corrosion, moisture, or pushed-back terminals.

3. 3

   Test the CAN Bus Lines: Measure the resistance across the CAN High and CAN Low pins at the ATC connector. A healthy CAN bus should read approximately 60 ohms. If it reads 120 ohms, there is an open circuit or a missing terminating resistor on the network.

4. 4

   Check for Related Codes: Look for other 'Off Line' codes (e.g., 14018 GOV Off Line, 14013 Transmission Off Line). If multiple modules are offline, the issue is likely a main CAN bus wiring fault rather than a failed ATC module.

1. 1

   Disconnect battery

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

2. 2

   Access ATC module

   Access the ATC module by removing the necessary cab trim panels (refer to your specific model's cab interior breakdown).

3. 3

   Disconnect harness

   Disconnect the electrical harness from the ATC module.

4. 4

   Remove faulty module

   Remove the mounting screws/bolts securing the module and remove the faulty unit.

5. 5

   Install new module

   Install the new ATC module and secure the mounting hardware.

6. 6

   Reconnect harness

   Reconnect the electrical harness, ensuring the connector clicks firmly into place.

7. 7

   Reconnect battery

   Reconnect the battery.

8. 8

   Clear fault code

   Turn the key to the ON position and use the ICU/Dash display or a diagnostic scan tool (like Jaltest or CNH EST) to clear the inactive 14019 fault code.

9. 9

   Test HVAC system

   Test the HVAC system in 'Auto' mode to verify the ATC module is communicating and regulating cab temperature properly.