Case IH 520613-19 - ACM – ACM: Rear hitch position control disconnected

The control module has lost the electrical signal from the rear hitch position control potentiometer (the dial/knob used by the operator to set the 3-point hitch height).

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect (Models 180, 200, 220, 240, 250, 280, 310, 340, 380)
• Case IH Steiger AFS Connect / Quadtrac
• Case IH Optum AFS Connect / Puma Series (Tier 4B / Stage V)

1. 1

   Monitor Live Data: Use the Case IH Electronic Service Tool (EST) or the AFS Pro display to monitor the 'Rear hitch - position control' channel. The reading should smoothly transition from 0 (fully anti-clockwise) to 100 (fully clockwise). If it reads blank or error, the connection is completely lost.

2. 2

   Inspect the Armrest Harness: Remove the armrest console cover and inspect the wiring harness connecting the rear hitch position control knob to the ACM. Look for pinched wires, backed-out pins, or disconnected plugs.

3. 3

   Check Voltage/Reference: Disconnect the potentiometer and check for a 5-volt reference signal and a good ground coming from the ACM.

4. 4

   Test the Potentiometer: Test the potentiometer for internal continuity. If it reads an open circuit (infinite resistance) across its sweep, the component has failed internally.

1. 1

   Power Down

   Turn off the tractor, remove the key, and turn off the battery disconnect switch to prevent shorting sensitive CAN-bus components.

2. 2

   Access the Armrest Internals

   Remove the retaining screws on the underside or perimeter of the armrest control console to lift the top cover plate.

3. 3

   Disconnect the Component

   Locate the rear hitch position control potentiometer. Depress the locking tab on the electrical connector and unplug it.

4. 4

   Replace the Potentiometer

   Remove the retaining nut or clips holding the potentiometer/knob assembly to the armrest bezel. Install the new potentiometer and secure it.

5. 5

   Reassemble and Reconnect

   Plug the electrical connector into the new potentiometer. Ensure the harness is routed away from pinch points before reinstalling the armrest cover.

6. 6

   Clear Codes and Calibrate

   Turn the battery disconnect back on and power up the tractor. Use the EST or the tractor's diagnostic menu to clear the 520613-19 fault code. You may need to perform a quick calibration of the armrest controls so the ACM learns the new potentiometer's minimum and maximum voltage values.