credit goes to dragon 300zx on another forum...
i decided to post this because i saw someone else asking about there onstar and them not having a fob and if they could use one... you might try this... i know on my last car from chevy it didnt come with one, but all the cars were capable of it. so just had to get one and associate it with the vehicle... here ya go.
The fix is at the end if you don't care about how I found it.
So, I have read the stories... "This is a dealer only fix...", "No Owner Fix Possible....", Etc.
When I got my cobalt the keyfob didn't work, the battery had died at one point and it was no longer associated with the car.
I did a butt load of research and found that there was no way to reset it like on my other chevy cars. I called the dealer and was told in fact there was no way to fix this other than going there and paying 50-60 bucks to have them reprogram it.
My car got rear ended a week later and all of the sudden the keyfob just started working.
So I suggest you just go get rear ended.............
Although this fixed my car I do not recommend you try this....
My GF drives a cobalt (hers is an 05 mine is an 06), her KF battery died recently and we couldn't get it working again.......
I hate dealer only fixes and was determined to find another option. I shouldn't have to pay them 50 bucks for 15 seconds....
So I searched and searched and searched, and eventually I found a post saying that pulling the fuse for the radio would reset the system.... No way, that's just to damn easy....
So I tried it, and it worked.. Here is what I did.
The Fix.
I pulled the interior fuse cover from the passenger seat.
I located and pulled the 10A fuse for the Radio (labeled RDO).
I turned the car to the on position to verify the radio was disabled.
I turned the car back off and removed the keys.
I waited 30 seconds (I'm a Network Engineer, we always wait thirty seconds after unplugging something).
I put the fuse back into the correct spot.
I then held down the lock and unlock key on the keyfob at the same time till the locks on the doors activated.
I then tested the keyfob and made sure it was locking and unlocking the doors and activating the security system.
This process did reset my security settings on her car so I had to go through the reset process (holding in the information and reset key at the same time then following the prompts).
The keyfob now works, and I didn't have to pay some ******* dealer $50 for 15 seconds.
