Cummins ISC CM2150 (2007-09) Fault Code: 441 PID: 168 SPN: 168 FMI: 1 Battery 1 Voltage - Data Valid but Below Normal Operational Range - Moderately Severe Level. ECM supply voltage is below the minimum system voltage level.

Verify the electronic control module (ECM) calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, recalibrate the ECM.

This fault code is logged when the ECM battery supply voltage drops below 6-VDC.

1)Verify that the ECM unswitched power supply is coming from the batteries and not the starter or other device. Check for possible weak batteries.
2)If the ECM unswitched battery supply is taken from the starter, check for low voltage during cranking. Low voltage during cranking can cause the ECM power supply to drop below specifications and log Fault Code 441.

Possible repairs:

1)Tighten the loose connections and clean the terminals.
2)Charge or replace the battery(s).
3)Replace the fuse.
4)Repair or replace the OEM power harness.
5)Repair or replace the damaged wires.