Case IH 518557-01 - ACM – ACM (Armrest Control Module): EHR settings adjustment knob internal failure

The fault code indicates an internal failure of the EHR (Electro-Hydraulic Remote / Electronic Hitch Control) settings adjustment knob. The potentiometer or encoder inside the knob assembly is malfunctioning, sending an out-of-range, erratic, or dead signal to the control module, preventing the operator from adjusting the hydraulic flow or hitch settings.

• MAGNUM AFS Connect
• Magnum Series (180, 190, 210, 225, 235-340, 260, 290)
• Steiger Series (350 to 600 HP models)
• Puma Series (175, 210)

1. 1

   Navigate to the EHR settings screen or the Rear Hitch/Automatic Depth Control (ADC) screen on the AFS Pro display. Turn the EHR adjustment knob clockwise and counterclockwise to see if the values change. If they do not change or jump erratically, the knob's internal potentiometer is faulty.

2. 2

   Use a diagnostic tool to read the fault memory and verify there are no broader ACM communication errors (such as code 1012 - No communication with the ACM) which would point to a main harness issue rather than the knob.

3. 3

   Inspect the wiring harness and connectors under the armrest compartment for damage, loose pins, or corrosion before condemning the hardware.

1. 1

   Power Down

   Turn off the tractor key-start and disconnect the battery power to prevent electrostatic discharge damage to the ACM.

2. 2

   Access the Armrest Internals

   Remove the armrest cover/panel to access the integrated control panel, the EHR adjustment knobs, and the ACM.

3. 3

   Component Replacement

   If the diagnostic checks isolated the failure to the knob itself, replace the EHR settings adjustment knob/potentiometer assembly (often integrated into the electrohydraulic remote lever control panel). If the ACM is failing to process the signal despite a working knob and good wiring, the ACM itself must be replaced.

4. 4

   Reassembly & Calibration

   Reconnect the wiring harnesses and reassemble the armrest. Power on the tractor and use the display setup menu or a diagnostic tool to calibrate the levers and knobs.