Case IH 168-01 - ACM – ACM: System Voltage Low / 12 V supply internal failure

The control module is detecting an electrical power supply voltage that has dropped below the acceptable operating threshold, or there is an internal failure within the module's 12-volt power distribution circuit.

• MAGNUM AFS Connect
• Magnum Series (180, 200, 220, 240, 250, 280, 310, 340, 380 CVT and Full Power Shift)
• Steiger Series
• Puma Series
• Maxxum Series
• Optum Series

1. 1

   Verify that the battery is fully charged and the alternator is producing the correct voltage

2. 2

   Check the fuses supplying the ACM, specifically the unswitched B+ fuse (F-014 10A) and the switched B+ fuse (F-063 10A)

3. 3

   Inspect the power relay for proper operation

4. 4

   Inspect the battery wires from the ACM back to the battery compartment

5. 5

   Check the power and ground connections directly at the ACM for loose pins, moisture, or corrosion

1. 1

   Clean Power Source

   Disconnect the batteries. Thoroughly rinse the battery case and use fine-grade sandpaper to clean the terminals and cable clamps until the surfaces are bright and shiny. Coat the clamps and terminals with petroleum jelly or a silicone lubricant to prevent future voltage drops.

2. 2

   Repair Wiring/Fuses

   Replace any blown 10A ACM fuses. If you found chafed wires or corroded connectors during the diagnostic checks, repair or replace the affected harness sections.

3. 3

   Test the System

   Reconnect the batteries, turn the key on, and use the EST (Electronic Service Tool) to check if the 168-01 code changes from "Active" to "Stored".

4. 4

   Replace the ACM

   If external power and ground to the ACM test perfectly but the code remains active, the module has suffered an internal 12V supply failure. You must replace the Armrest Control Module.

5. 5

   Reprogramming

   After installing a new ACM, use the Case IH EST diagnostic tool to configure the module and flash the correct software (e.g., software part number 48010791 for Magnum AFS Connect).