I just washed my 300 pulled out of the parking lot and went to get gas. I turn my car off and while I'm pumping gas all the dash lights and the passenger airbag lights flicker and come on. The radio and air also turn on. No key on ignition. I drive a little bit and park. When I turn the car off and take the key out the car doesn't turn off immediately. It's like it hesitates to turn off and then roughly turns off. The check engine light, the ESP/BAS, and the lightning bolt light come on. I let it sit for a while trying to turn it on periodically. Sometimes it will barely and sometimes it will just keep turning over and won't start. All the dash lights keep flashing and doing what they were doing at the gas pump. There is also a light next to the lightning bolt light that flashes red but I believe it's a car alarm light so I don't know why it would be on. When I do have it on it would not let me accelerate in drive or reverse. It goes into gear fine though. Eventually I let it sit for a couple hours and it seemed to be running fine. I drove it back to my house (about 5 miles away). Check engine light still on. When I got back to my house and turned it off it did the same thing, hesitated before turning off then the passenger airbag light was flickering. Also when the pass. airbag light flickers the 3rd middle break light in the back also flickers in the same pattern. Someone please help me out I would really appreciate it. I am not very knowledgable in this subject fellas!! Thanks

 

When the check engine light comes on, it means that the computer has detected a fault somewhere in the system. It stores error codes in its memory that will help a technician diagnose what is wrong. You need to get the car hooked up to a code reader to read the codes stored in the computer. There are hundreds of possible codes and nobody here can guess which ones your car has. It could be something simple, it could be major. Many auto parts stores will read the codes for free. Otherwise you'll have to take it to a shop with the right equipment. They may charge you a fee. Once the technician has tracked down the error codes, you and he can decide where to go from there.

 

Todays cars require good battery and good connections. Weird things happen when there is a poor ground or a marginal battery. First thing I would recommend is disassembling and cleaning all battery and jump post connections both Positive and negative.
Have the battery tested, if marginal or over 5 years old replace it.
Do this stuff first.