Case IH 518559-03 - ACM – ACM: EHR lever A voltage high

The voltage signal from the EHR (Electro-Hydraulic Remote) Lever A (often designated as Lever 1) potentiometer is too high. In J1939 standard formatting, the "-03" Failure Mode Indicator (FMI) means "Voltage Above Normal, or Shorted to High Source." This condition typically occurs when the lever's signal circuit is shorted to a power source (such as the 5V or 12V reference line) or if the potentiometer has an open ground circuit, causing the voltage reading to max out.

• MAGNUM AFS Connect
• Magnum
• Steiger
• Puma
• Maxxum
• Optum

1. 1

   Verify ACM Configuration: Use the Case IH Electronic Service Tool (EST) or the tractor's Pro Vision display to ensure the ACM is configured correctly to rule out false codes.

2. 2

   Inspect the Wiring Harness: Remove the armrest console cover and inspect the wiring harness connecting EHR Lever A to the ACM for pinched wires, chafing, or exposed copper that could cause a short to power.

3. 3

   Check Connectors: Disconnect the EHR lever and the ACM connectors. Inspect for bent pins, corrosion, or moisture, which can cause resistance issues or bridge the power and signal pins.

4. 4

   Test the Potentiometer: Using a multimeter, check the voltage and resistance sweep of the EHR Lever A potentiometer to see if the ground circuit is open or the signal voltage does not smoothly change.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical spikes.

2. 2

   Access the Armrest

   Remove the retaining screws on the armrest console to lift the cover and access the EHR lever bank and the ACM.

3. 3

   Disconnect the Lever

   Locate EHR Lever A (the first lever in the sequence) and unplug its electrical connector.

4. 4

   Replace the Component

   If the harness is damaged, repair the wiring. If the lever failed the multimeter test, unbolt the faulty EHR lever assembly from the mounting panel and install the new lever.

5. 5

   Reassemble

   Plug the connector into the new lever, reinstall the armrest cover, and reconnect the battery.

6. 6

   Calibrate the Lever

   You must perform an EHR lever calibration after replacing the lever or the ACM. This can be done via the tractor's display (e.g., navigating to the H-Menu or calibration screens, pulling the lever into the raise/detent positions as prompted) or by using the EST software.