Case IH 518684-02 - ACM – ACM: Hitch settings selector knob switch circuit fault.

The system has detected an erratic, intermittent, or incorrect data signal (indicated by the -02 Failure Mode Indicator) from the hitch settings selector knob switch circuit. This rotary encoder/knob is used by the operator to adjust hitch parameters such as draft control, position limit, drop rate, and slip limit. The fault indicates that the control module is receiving an implausible or unstable voltage/resistance reading from the switch potentiometer or its wiring.

• MAGNUM AFS Connect
• Puma series (130, 145, 160, 175 CVX)
• Maxxum series (110CVX, 120CVX, 130CVX, ActiveDrive 8)
• Optum CVXDrive series
• Magnum series (235–340 Series 4, 290)
• Steiger / Quadtrac series
• Vestrum CVXDrive series

1. 1

   Reset the Controller: Power cycle the tractor or pull the hitch/ACM fuse for 30 seconds to reset the controller and see if the code changes from 'Permanent' to 'Pending'.

2. 2

   Check the 5-Volt Reference: Verify that the 5-volt reference circuit supplying the armrest sensors is within limits (check for related codes like Hitch 1014 or 1015, which indicate 5V reference faults).

3. 3

   Inspect Wiring and Connectors: Inspect the wiring harness and connector pins at the hitch settings selector switch and the ACM. Look for corrosion, backed-out pins, or wire chafing inside the armrest console.

4. 4

   Test the Potentiometer: Using a multimeter, test the resistance of the hitch settings selector potentiometer while slowly turning the knob. Look for dead spots, sudden drop-offs, or open circuits in the sweep.

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the battery to prevent short circuits while working inside the armrest.

2. 2

   Access the Armrest Internals

   Remove the retaining screws securing the Multicontroller armrest console top cover. Awkwardly lift the cover to gain access to the internal switch modules and the ACM.

3. 3

   Remove the Faulty Switch

   Locate the hitch settings selector knob assembly. Disconnect its electrical harness connector. Remove the retaining hardware holding the switch assembly to the console.

4. 4

   Index the New Knob

   When installing the new rotary knob/switch, it must be correctly timed/clocked with the splined shaft it fits onto. If it is off by a notch, the hitch will not cancel out the lifting process correctly. Ensure the arrow on the outer knob points exactly at the "Position" setting when turned all the way clockwise.

5. 5

   Reassembly

   Secure the new switch assembly, reconnect the electrical harness, and carefully reinstall the armrest console cover, ensuring no wires are pinched.

6. 6

   Calibration/Testing

   Reconnect the battery. Turn the key on, clear the stored fault codes via the AFS display or diagnostic tool, and test the hitch in Draft, Position, and Mixed modes to verify proper operation.