ColoradoDave

The message "Service Battery Charging System" is not the DTC code, its the human readable equivalent of a check engine light for problems that are managed by the BCM. The BCM has interpreted there is a charging problem. This is based on any number of sensors readings the ECM and the BCM use to interpret the health of the charging system, exactly as your research that you posted has shown. Once the BCM determines there is a problem, it will set a DTC. The BCM then sends a message to the DIC (a human readable message...not the actual DTC) so you know there is a problem. What Rob is saying without specifically saying it is that you'll need something more than an OBDII scanner to read the GM specific code related to this DTC. Because this is not an emission related DTC, DIY handheld scanners will not be able to read the DTC and will report all is fine (as has been noted twice in this thread). Scanners that are able to communicate over the GM bus, have the necessary GM modules loaded and can communicate with modules like the BCM will be able read the actual DTC that is triggering the DIC human readable message you see. You need the DTC code (as well as specific diagnostic procedures related to the DTC) to be able to correctly diagnose the issue, particularly since basic diagnostic work done so far has not found any obvious problems. Hope this helps.

I understand what you are saying, however, does your scanner say you are ready for emission testing?