2013 Mustang V-6, son lost one of my ignition keys so had to purchase new one and have it programmed for ignition, since then I purchased another key and trying to program myself. I've gone thru the sequence found on the internet but how do I know if the key is programmed accurately? I've heard that an unprogrammed key will start the ignition but the car will eventually die. How long will the car run before stalling?

 

If key is not programmed will not start the car.

 

As said, car will not start without it programmed... you don't have to worry about it cutting off on you. If it starts it is programmed. If it is an aftermarket key you have to do a sequence different than programming the chip to get the remote to work for the doors though.

 

thanks, the sequence must have worked because my spare key starts the car.

 

will it lock/unlock the doors too?

 

i have a 3rd key but I cant get the remote to work and stay that way. I got it to work a few times but then it quits working . The orginal ones have always worked no problem but not thr 3rd one. Maybe I need a new battery in the new one.

 

I would try the battery for sure.