Case IH 518683-00 - ACM – ACM: Rear hitch settings selector knob internal failure

Position Command value received over the CAN data bus from the armrest has failed, typically pointing to a failed potentiometer or internal switch failure within the control knob.

• MAGNUM AFS Connect
• Case IH Magnum series (e.g., 180–340, Series 4)
• Case IH Steiger series
• Case IH Maxxum series

1. 1

   Verify CAN data bus communication between the Armrest Controller Module (ACM) and the UCM.

2. 2

   Check for related ACM communication fault codes (such as 1012 - No communication with the ACM).

3. 3

   Test the voltage and resistance of the rear hitch position control potentiometers to ensure they are not open, shorted, or misadjusted (which typically trigger codes like 1018 or 18015/18016).