Case IH 518566-06 - ACM – ACM: EHR lever H voltage low

The signal voltage from the Electro-Hydraulic Remote (EHR) lever 'H' has dropped below the minimum acceptable threshold (typically below 0.5V). This is usually caused by a short to ground in the signal wire, an open circuit in the signal or 5V reference circuit, or a failed potentiometer or Hall-effect sensor inside the EHR lever.

• MAGNUM AFS Connect
• Magnum Series
• Steiger / Quadtrac Series
• Puma Series
• Optum Series

1. 1

   Remove the armrest cover and visually inspect the wiring harness leading to EHR lever H for pinched wires, chafing, or disconnected plugs.

2. 2

   Disconnect the lever and inspect the pins for corrosion, moisture, or backed-out terminals.

3. 3

   With the key ON, probe the harness side of the lever connector to verify that there is a steady 5V reference and a good ground.

4. 4

   Perform a swap test by swapping the electrical connection of Lever H with an adjacent lever (e.g., Lever G or Lever 1). If the fault code changes to the new lever's position, the lever itself has failed. If the fault code remains 'EHR lever H voltage low', the issue is in the wiring harness or the ACM itself.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery ground cable to prevent electrical spikes.

2. 2

   Disassemble Armrest

   Remove the retaining screws holding the upper armrest console cover/bezel in place to expose the EHR lever modules.

3. 3

   Remove the Faulty Lever

   Disconnect the electrical pigtail from EHR lever H. Remove the mounting screws or retaining clips securing the lever assembly to the armrest bracket.

4. 4

   Install the New Lever

   Seat the replacement lever into the bracket, secure the fasteners, and plug in the electrical connector. Transfer the color-coded cap from the old lever to the new one if the new part does not include it.

5. 5

   Reassemble

   Reinstall the armrest cover and reconnect the battery.

6. 6

   Calibration

   Perform the EHR Lever Calibration procedure through the tractor's Pro 700/1200 display monitor or using the Case IH Electronic Service Tool (EST). This allows the ACM to learn the new lever's specific minimum, maximum, and neutral voltage values.