Q: Check system charge light

Hello. Thanks for writing in. The check charging system and battery light is illuminating because the battery or alternator is failing in some way, or the sensors that monitor them are failing. The battery may not be holding the charge, or the alternator may not be charging the battery enough. Either way, this is a critical system in your vehicle and it will not drive without it. There are several tests you can perform at home if you choose to. You will need a voltmeter. First test the voltage at the battery when the car is idling. Then rev the engine while in park and test the voltage at 2000RPMs. The voltage should remain between 12-14 volts. Any lower and the alternator is not sending the battery enough power. Any more, and the alternator is working too hard. Either way it is likely the alternator or battery will need to be replaced. Until further testing is done, we cant tell.