Case IH 51105 – AUX Controller: Invalid Software Instruction Executed

This code indicates a logic or memory error within the controller. The failure mode is a software problem in most cases, though there is a small chance it is a hardware failure within the controller itself.

• MX Magnum
• MX180
• MX200
• MX210
• MX220
• MX230
• MX240
• MX255
• MX270
• MX285
• STX275
• STX325
• STX375
• STX440
• STX450
• TG210
• TG230
• TG255
• TG285

1. 1

   Check power and ground connections to the AUX controller (specifically connector C053) to ensure clean, tight connections, as poor voltage can cause software glitches

2. 2

   Perform a relay 'click' test by turning the key ON for more than two seconds, then OFF, and listening/feeling for an internal relay click on the controller

3. 3

   Note if the problem is intermittent and sensitive to temperature changes, which indicates a progressively deteriorating controller

4. 4

   Perform a soft reset: clear the fault code, shut down the tractor completely, and restart it to rule out a momentary software glitch

1. 1

   Inspect Wiring

   Locate the AUX controller at the rear of the tractor. Inspect the main wiring harness, focusing on the power supply and ground wires. Clean any corrosion from the ground terminals and ensure they are tight.

2. 2

   Clear and Retest

   Use the tractor's diagnostic menu or an Electronic Service Tool (EST) to clear the fault code. Cycle the ignition.

3. 3

   Perform Relay Test

   Perform the key-on/key-off relay click test mentioned in the diagnostics section.

4. 4

   Replace Controller

   If the wiring is good, the code immediately returns upon restart, or the controller fails the relay click test, the AUX controller must be replaced.

5. 5

   Calibrate

   If a new AUX controller is installed, you will need to perform the hitch/remote valve calibration procedure so the new controller can learn the extend/retract limits of the remote levers.