Case IH 55.00 - ACML – ACML: Battery voltage out of range, set as indicator

The control module is receiving a supply voltage that falls outside of its programmed acceptable operating parameters (either too high, such as an alternator overcharging, or too low, such as a failing battery or excessive voltage drop in the wiring).

• MAXXUM T4E
• VESTRUM CVX
• Case IH MAXXUM 135
• Case IH PUMA 220

1. 1

   Verify base battery voltage (should be ~12.6V resting) and alternator output (should be ~13.5V - 14.5V running).

2. 2

   Inspect the main wiring harness leading to the armrest console for chafing, pinched wires, or loose connector pins.

3. 3

   Measure the actual voltage arriving at the ACML power pins and compare it to the battery voltage to check for high resistance.

4. 4

   Check the cab and armrest ground straps for poor connections.

1. 1

   Repair voltage supply issue

   Fix the underlying voltage supply issue by replacing a faulty alternator, repairing a corroded wire, or cleaning a ground point as identified in diagnostics.

2. 2

   Clear fault codes

   Clear the fault codes via the tractor's diagnostic menu or AFS Pro display.

3. 3

   Replace and calibrate ACML

   If the wiring and charging system are perfectly within range but the ACML still reports an out-of-range voltage, replace the ACML module and perform OEM calibration of components like the EDC, PTO, steering, and front suspension.