Q: Hello my 2012 Buick lacrose service battery charging system light is coming on

If an engine fault causes enough loss in RPM at idle, the charging system warning light could come on. Another possibility is the charging system and/or battery are faulty and thus there is inadequate power to run the ignition system, fuel pump, etc. When that happens the engine tends to die. The most common scenario though is a battery/charging system fault and so the first thing to do is check charging system output against factory specifications. It is also possible that a failed serpentine belt is not properly driving the alternator; that should be checked, too. The battery should be carefully evaluated in a load test. Batteries are very important. If the battery only has a marginal pass on the load test you should just simply install a new battery to reduce diagnostic headaches. To have the issue you are writing in about diagnosed and resolved, please request an alternator/battery inspection/replacement and the responding certified mechanic from YourMechanic will get this resolved for you promptly, right at your location. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.