Case IH 12023 – Remote AUX Controller: Invalid Source Address Controller

A Controller Area Network (CAN) bus communication error indicating that a specific control module (Remote AUX Controller) is broadcasting an unrecognized, unconfigured, or invalid source address to the rest of the system.

• STX Steiger
• Magnum
• Steiger
• Puma

1. 1

   Verify if the Remote AUX Controller or any other CAN module was recently replaced and left unprogrammed

2. 2

   Perform a CAN Bus Network Scan using the CNH Electronic Service Tool (EST) to check if AUX67 or AUX89 controllers are missing or reporting a corrupted ID

3. 3

   Inspect the CAN bus wiring harness connecting to the rear remote valve controllers for corrosion, moisture, damaged pins, or voltage drops

4. 4

   Verify that the software on the AUX controller matches the rest of the tractor's configuration to rule out a software mismatch

1. 1

   Connect Diagnostic Tool

   Hook up the CNH EST laptop to the tractor's diagnostic port.

2. 2

   Reconfigure the Module

   Navigate to the controller configuration menu. Attempt to re-address or re-flash the software for the affected Remote AUX Controller (AUX67 or AUX89).

3. 3

   Perform CAN Bus Reset

   Once the module is re-addressed, clear the inactive fault codes. Turn the key off, wait for the tractor's electrical system to power down completely (battery relay click), and turn the key back on.

4. 4

   Module Replacement

   If the EST cannot communicate with the AUX controller, or if the controller repeatedly drops its address and triggers code 12023 again, the internal logic board has failed and you must physically replace the Remote Valve Controller mounted on the rear hydraulic valve stack.

5. 5

   Calibration

   If a new controller is installed, use the EST to program its network address and perform a remote valve calibration procedure to ensure proper flow and lever response.