Case IH 51146 – AUX Controller: Invalid Software Instruction Executed

The controller attempted to execute an invalid software command (AUX 1 type 1st instance). This is usually caused by a software problem, but there is a small chance of a hardware problem within the controller.

• MX Magnum
• Case IH MX Series
• Case IH TG Series
• Case IH Magnum Series
• Case IH Steiger Series

1. 1

   Inspect Power Supply: Verify that the AUX controller has a solid, clean connection to the battery.

2. 2

   Inspect Ground: Check that the controller is properly grounded. Specifically, inspect connector C053 for corrosion, loose pins, or damaged wires.

3. 3

   Clear and Retest: Clear the active fault code from the system.

1. 1

   Trace wiring harness

   Locate the AUX controller and trace its wiring harness back to the battery and ground points.

2. 2

   Clean connector C053

   Disconnect connector C053, clean the contacts with electrical contact cleaner, and ensure the ground terminal is securely fastened to bare metal.

3. 3

   Clear fault code

   Reconnect the harness and use your diagnostic tool/monitor to clear the 51146 fault code.

4. 4

   Cycle system

   Shut down the tractor completely, wait a few moments, and restart the engine to cycle the system.

5. 5

   Monitor display

   Monitor the dash/display. If the fault code does not return, the issue was likely a transient voltage drop or poor ground causing a software glitch.

6. 6

   Contact PSM / Re-flash software

   If the fault code appears again, contact your district Product Support Manager (PSM). The controller will likely need an OEM software re-flash or update via the dealer's Electronic Service Tool (EST) before condemning the hardware.