I had a problem with my car not turning on. It was giving me strange error messages in the dash and wouldn't let me shift out of park. I disconnected hat the negative battery terminal and did a reset. That didn't work which made me panic so I tried again, still didn't work. So now we call the auto club. I think I'm going to have to get it towed to the dealer. Somehow the tow truck guy gets the car into neutral and rolls it out of the driveway. He can't get it to go back into neutral again so he can't put it on the flatbed. Another type of tow truck arrives and he has a battery booster unit. As soon as he hooks that up the car fires right up and starts going through the normal reset routine. So now we think the 12 volt battery is weak. Another guy who does battery replacement comes and tests the battery. It's 100 percent good. So now I decide I'm not getting it towed to the dealer and pay for diagnosis to tell me the same thing I just got done for free. Then I remember something from when I drove junk cars 40 years ago. Corroded battery connections cause cars not to start or the computer not to function properly due to low voltage. So i am cleaning them up myself and saving at least 2 to 3 hundred dollars. Bottom line is don't panic and always start with simplest fix first. Hope this advice saves you a lot of money too!