Case IH 518594-13 - ACM – ACM: Front PTO engage switch sensor disagreement

This fault indicates that the control module is receiving conflicting or implausible electrical signals from the Front Power Take-Off (PTO) engagement switch. A 'disagreement' means that the dual circuits inside the switch are not reporting the same physical position, or the voltage levels do not match the expected parameters for the switch's current state.

• MAGNUM AFS Connect
• Magnum 180 AFS Connect
• Magnum 200 AFS Connect
• Magnum 220 AFS Connect
• Magnum 240 AFS Connect
• Magnum 250 AFS Connect
• Magnum 280 AFS Connect
• Magnum 310 AFS Connect
• Magnum 340 AFS Connect
• Magnum 380 AFS Connect
• Magnum 400 AFS Connect
• Steiger AFS Connect
• Optum

1. 1

   Inspect the physical Front PTO switch on the armrest. Check if the switch is physically sticking, damaged, or if debris is preventing it from fully clicking into the ON or OFF position.

2. 2

   Access the wiring beneath the armrest panel. Inspect the connector at the Front PTO switch and the harness routing to the ACM for loose pins, chafed wires, or corrosion.

3. 3

   Connect a compatible diagnostic scan tool (such as the Case IH Electronic Service Tool or Jaltest) to the tractor's diagnostic port. Monitor the live data for the ACM Front PTO switch inputs. Observe if the switch states toggle correctly when physically moved.

4. 4

   Look for accompanying ACM codes that might indicate a hard electrical fault, such as 518594-06 (Low voltage) or 518594-03 (High voltage).

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the battery to prevent accidental PTO engagement or electrical shorts during repair.

2. 2

   Access the Switch

   Carefully remove the necessary trim panels or the top cover of the AFS Connect multi-function armrest to access the underside of the switch cluster.

3. 3

   Disconnect

   Unplug the electrical harness connector from the bottom of the Front PTO switch.

4. 4

   Remove

   Depress the plastic retaining tabs on the sides of the switch body and push the switch upward and out of the armrest console.

5. 5

   Install

   Insert the replacement Front PTO switch into the armrest slot from the top until the retaining tabs click securely into place.

6. 6

   Reconnect

   Plug the electrical harness connector back into the new switch.

7. 7

   Reassemble

   Reinstall the armrest trim panels.

8. 8

   Clear Codes & Test

   Reconnect the battery, turn the ignition on, and use a diagnostic scan tool to clear the 518594-13 fault code from the ACM. Start the tractor and test the Front PTO engagement to verify the repair.