Case IH 56.00 - ACML – ACML: 12VRef voltage out of range

The 12-volt reference (12VRef) circuit supplied by the control module to various sensors or switches is reading outside of its expected operating parameters. This typically means the 12V reference circuit is either shorted to ground, shorted to power, or experiencing an open circuit, preventing the module from receiving accurate signals from the components it powers.

• MAXXUM T4E
• VESTRUM CVX
• Case IH MAXXUM 135 - MULTICONTROLLER ACTIVEDRIVE 8 TRACTOR - STAGE V
• Puma
• Maxxum CVXDrive/Multicontroller

1. 1

   Inspect the wiring harness connecting the ACML to the armrest sensors/switches for chafing, pinches, or exposed wires that could cause a short to ground or short to power.

2. 2

   Disconnect the sensors on the 12V reference circuit one by one to see if the voltage returns to normal (which would indicate a shorted sensor rather than a faulty module).

3. 3

   Check the main power and ground pins at the ACML connector to ensure the module itself is receiving proper voltage.

1. 1

   Replace module

   If the diagnostic checks point to an internal failure of the 12V reference driver within the module itself, replace the ACML (Armrest Control Module).

2. 2

   Recalibrate controls

   Recalibrate the armrest controls (such as the EHR levers and Multicontroller joystick) using the tractor's H1 universal controller menu or electronic service tool.