Case IH 51262 – Remote Auxiliary Controller (AUX67 / AUX89 / MU8): Implement Sensor supply out of range High

The voltage supply to the implement/scraper position sensor is reading higher than the acceptable upper limit. This is typically caused by a short circuit to a 12V power source, a failed sensor internally shorting, or a malfunctioning controller sending excessive voltage.

• MX Magnum
• STX Steiger
• Steiger 4WD Tractors
• Magnum Series
• MX Magnum Series
• TG Series
• TG210
• TG230
• TG255
• TG285
• Puma Series

1. 1

   Relay Click Test: Open the controller cover on the back of the tractor, turn the ignition key ON for more than two seconds, then turn it OFF. Listen or feel for a relay 'click' inside the controller (no click indicates a failed controller).

2. 2

   Temperature Sensitivity Check: Note if the problem is intermittent, as intermittent faults here are often caused by temperature changes acting on a progressively deteriorating Remote AUX controller.

3. 3

   Harness Inspection: Trace the wiring harness from the implement/scraper sensor back to the AUX controller, looking for rubbed or melted wire insulation that could be shorting the sensor's supply wire directly to a 12V power source.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent electrical spikes.

2. 2

   Inspect and Test Wiring

   Disconnect the implement/scraper sensor. Use a multimeter to check the voltage on the supply pin of the harness connector (with the battery temporarily reconnected and key ON). If it reads battery voltage (12V+) instead of the standard 5V reference, there is a short in the harness or a bad controller.

3. 3

   Test the Controller

   Perform the relay click test. If the controller fails the test, unbolt the Remote AUX controller from the rear of the tractor, disconnect the multi-pin harnesses, and install a replacement unit.

4. 4

   Replace the Sensor

   If the controller and wiring test fine, the sensor itself has failed internally. Unbolt the implement/scraper feedback sensor from its mounting bracket, disconnect the pigtail, and install the new sensor.

5. 5

   Clear Codes and Calibrate

   Reconnect the battery. Use the tractor's diagnostic display or a service tool to clear the factory memory and recalibrate the implement feedback limits.