I have been working on my friends 2005 Cobalt and it doesn't happen all the time but she says when she puts it into park if the doors don't unlock it wont shift out of park. and it will just randomly start working. I thought it was the shift solenoid but its good. Then i though it was the sticky parking brake button making it not come out of park thinking the parking brake was engaged. Tested it about 40 times putting it in gear then putting it, shutting the car off taking the key out locking and unlocking the doors in every pattern you can think of over and over again about 30 times like I said and it worked fine. She took it to work and got home she noticed the doors didn't lock and it would not come out of park. Im just completely lost, any help is appreciated.