I left my Volt to have some body work done on the front driver fender for 2 weeks. When I received it back, the "Check Engine" light was on. It stayed on. I drove it home normally. Then I plugged it into a 110 home charger and the green charging light indicator did nothing. I turned the car on and went to the energy/charge screen and it said "unable to charge" in a white box. Any suggestions?