Case IH 520616-13 - ACM – ACM: Rear PTO engage switch sensor disagreement

The yellow PTO engagement switch on the armrest utilizes a dual-channel (redundant) internal sensor/contact system. This fault is triggered when the control module receives conflicting signals from the switch (e.g., Channel 1 indicates Engaged while Channel 2 indicates Disengaged). The system disables the rear PTO to prevent unintended implement operation.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect
• Steiger AFS Connect

1. 1

   Check the mechanical action of the yellow Rear PTO switch on the armrest. Ensure it pulls up and pushes down smoothly without sticking or feeling spongy. Debris can sometimes jam the switch mechanism.

2. 2

   Remove the armrest trim to access the underside of the switch and inspect the electrical connector for loose pins, backed-out wires, or corrosion.

3. 3

   Connect the Case IH Electronic Service Tool (EST) and monitor the ACM live data for the Rear PTO Switch (Channels 1 and 2). Toggle the switch; if one channel fails to change state, the switch has failed internally. If both read erratically, suspect a wiring harness issue or poor ground to the ACM.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the negative battery cable to prevent electrical shorts or accidental module spikes.

2. 2

   Access the Switch

   Carefully remove the retaining screws or pry up the cosmetic trim bezel on the MultiControl Armrest to expose the underside of the switch bank.

3. 3

   Disconnect

   Locate the Rear PTO engage switch and unplug its electrical harness connector.

4. 4

   Remove the Switch

   Squeeze the plastic retaining tabs on the sides of the switch body and push it upward through the armrest bezel to remove it.

5. 5

   Install the New Part

   Push the new PTO switch down into the bezel until the retaining tabs click securely into place.

6. 6

   Reconnect

   Plug the electrical harness connector into the new switch, ensuring the locking tab engages.

7. 7

   Reassemble

   Reinstall the armrest trim panel and secure any screws.

8. 8

   Clear and Test

   Reconnect the battery. Turn the ignition on, connect the EST, and clear the 520616-13 inactive fault code. Start the tractor and test the rear PTO engagement to verify the repair.