Case IH 520613-06 - ACM – ACM: Rear hitch working position voltage low

This fault condition indicates that the signal voltage coming from the rear hitch position sensor is dropping below the acceptable minimum threshold. It typically means the sensor's circuit has an open connection, a short to ground, or the sensor itself has failed internally.

• MAGNUM AFS Connect
• Case IH Magnum 235 – 340 (Series 4)

1. 1

   Check the 5-Volt Reference: Verify that the 5-volt reference from the ACM is present at the sensor connector.

2. 2

   Inspect the Wiring Harness: Check the wiring between the rear hitch rockshaft position potentiometer and the Armrest Controller Module for an open circuit or a short to ground.

3. 3

   Check Mechanical Linkage: Verify that the physical linkage connecting the rockshaft to the potentiometer is not broken, disconnected, or mechanically misadjusted.

4. 4

   Check CAN Communication: Ensure there are no underlying communication errors with the ACM (such as code 1012) which could cause erroneous sensor readings.

1. 1

   Access the Sensor

   Locate the rear hitch rockshaft position potentiometer at the rear of the tractor, typically mounted near the upper lift arms/rockshaft.

2. 2

   Test the Circuit

   Disconnect the sensor. Using a multimeter, verify the 5V supply and ground from the ACM on the harness side.

3. 3

   Adjust or Replace

   If the wiring is intact and the voltage supply is correct, the potentiometer has failed internally or is misadjusted. Attempt to adjust the sensor linkage. If the voltage remains out of range (too low), remove the faulty potentiometer and install a replacement.

4. 4

   Calibrate

   After replacing or adjusting the rear hitch position control potentiometer, you must perform a hitch calibration through the tractor's display monitor so the ACM can learn the new minimum and maximum voltage limits of the sensor's travel.

5. 5

   Clear Codes

   Use a diagnostic tool or the tractor's display to clear the stored ACM fault codes.