Case IH 518567-03 - ACM – ACM: EHR Valve Selector Knob Voltage Too High

Fault code 518567-03 indicates that the voltage signal from the EHR (Electro-Hydraulic Remote) valve selector knob is too high. The controller is receiving a voltage reading from the selector knob's potentiometer or switch that exceeds the maximum expected threshold. This is typically caused by a short to a power source, an open ground circuit, or an internal failure of the switch itself.

• MAGNUM AFS Connect
• Case IH Magnum
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• Case IH Puma
• Case IH Optum
• Case IH Maxxum

1. 1

   Use the Case IH Electronic Service Tool (EST) or the tractor's advanced display monitor to view the live voltage of the EHR valve selector knob (verify if the voltage is stuck at a constant high value, typically 5V)

2. 2

   Check the ground wire leading to the EHR selector switch for an open circuit, which will cause the signal voltage to float high

3. 3

   Inspect the wiring harness between the EHR selector switch and the ACM for pinched wires or rubbed insulation that could cause the signal wire to short to a 12V or 5V power source

4. 4

   Remove the armrest cover and inspect the electrical connector at the switch for corrosion, moisture, or backed-out pins that could cause an open circuit

5. 5

   Disconnect the switch and test it with a multimeter by checking the resistance sweep of the potentiometer as you turn the knob (infinite or unsmooth resistance indicates an internal fault)

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the negative battery cable to prevent electrical damage or accidental shorting.

2. 2

   Access the Armrest Internals

   Remove the retaining screws on the underside or perimeter of the Multicontroller armrest. Carefully lift the top cover/bezel to access the internal wiring and switches.

3. 3

   Locate the Component

   Identify the EHR valve selector knob assembly and its corresponding wiring harness.

4. 4

   Disconnect and Inspect

   Unplug the electrical connector from the switch. If the diagnostic checks revealed a broken wire or damaged connector pin, repair the harness using a CNH approved terminal repair kit.

5. 5

   Replace the Switch

   If the switch itself failed testing, unclip or unscrew the faulty EHR selector switch from the armrest mounting frame and install the new OEM replacement part.

6. 6

   Reassembly

   Reconnect the electrical connector. Carefully seat the armrest cover back into place, ensuring no wires are pinched, and reinstall the retaining screws.

7. 7

   Clear Codes and Calibrate

   Reconnect the battery and turn the key on. Use the EST or the tractor's display to clear the inactive 518567-03 fault code. Test the EHR selector knob to ensure it properly toggles between the remote valves without logging a new code. (Note: Some armrest components may require a quick calibration routine via the EST after replacement).