Case IH 518560-06 - ACM – ACM: ACM: EHR lever B voltage low

The fault indicates a low voltage condition on the signal circuit for Electro-Hydraulic Remote (EHR) lever B. The signal voltage returning to the controller has dropped below the minimum threshold, which is usually caused by a short to ground, an open circuit/broken wire, or a failed potentiometer inside the lever assembly.

• MAGNUM AFS Connect
• Case IH Magnum Series
• Magnum 235-340
• Magnum 245

1. 1

   Check system battery voltage with the tractor running (must be between 12.0V and 14.0V) to rule out false sensor codes from low voltage.

2. 2

   Inspect all fuses related to the Tractor Control Unit (TCU), ACM, and EHR control units.

3. 3

   Check if the EHR lever has lost its calibration, which can trigger erratic fault codes.

4. 4

   Inspect the wiring harness and connectors between EHR lever B and the ACM for chafed wires, pinched harnesses in the armrest pivot, or loose/backed-out pins.

5. 5

   Perform a continuity test on the wiring harness and check for a short to ground.

1. 1

   Recalibrate the EHR Lever

   Enter the tractor's diagnostic menu via the instrument cluster. Navigate to the EHR menus and perform the EHR lever calibration procedure. Ensure the lever is in the neutral position before starting.

2. 2

   Clear and Retest

   After calibration, clear the fault codes and test the lever for normal operation.

3. 3

   Test the Circuit

   If the code returns immediately, disconnect the EHR lever and use a multimeter to check the 5-volt reference and ground circuits coming from the ACM.

4. 4

   Replace the Component

   If the wiring harness tests good (no shorts to ground, no open circuits) and the ACM is outputting the correct reference voltage, the potentiometer inside EHR lever B has failed. Remove the armrest console trim, disconnect the faulty lever, and replace it with a new unit.

5. 5

   Final Calibration

   Any time an EHR lever or ACM is replaced, you must perform the EHR lever calibration procedure again before the system will operate.