Hopefully the original battery is going bad. It has been turning over weakly the past two weeks. I placed the battery on a charger, after charging my car won’t start. The error I’m getting is B210A - System Voltage Low (WCM). I have noticed slightly lower mpg. Right around 15.5. I do drive city but 17+ is normal. I was not able to jump the car either. I would appreciate any insight you could give me. Happy holidays!