Just replaced key cylinder and car won't start

Is the key chipped? Look at the hilt of the old key and see if it has PK3 stamped into it. If it does then the new key will have to be programmed to the car. Does it try to turn over?

Not true my 2003 and my 2005 do not have transponder keys. The security works some I'm not sure how.

I have a chevy impala 2002 that needs the ignition housing replaced i have the original key and cylender. Will the car need to be reprogrammed?

We have a 2003 Chevy Impala we change the key ignition and it's like it doesn't do anything is there a way or do you have to reset the key ignition and it does not have a key chip

we have a 2003 Chevy Impala to change the ignition and now it won't turn over it doesn't have a computer chip in the key is there something that we have to program with the key

If you change it ignition cylinder including the lock and the keys you will have to reprogram it and you can do it yourself through your factory radio; you do not have to take it to a dealer. You would need a fully charged battery. You will need to sit inside the car and go through the steps that comes with the brand new cylinder lock and keys. It involves a series of on and off and counting. Another precaution is to disarm the theft alarm system through your radio prior to reprogramming. The reprogramming stamps are on the or included with your set of new keys and lock cylinder. I went through all these steps and my car cranked up fine but I was afraid to rearm the death alarm system through my radio because I thought the new key in the ignition May trigger the BCM that somebody is trying to steal it so I do not intend to take that chance. It may or may not work I don't know but right now it's been almost a year now and I've had not one single problem with the ignition. The remote on off horns and locks still work. YOLO fob will not work unless you reprogram them through your radio. Believe it or not your radio has a procedure whereby you can reprogram your fobs or any new ones you made buy. But they can only be reprogrammed to your new lock cylinder. If you buy new remote transmitters they will have to be reprogrammed through your radio. it's a little too extensive to go through here but it's easily done once you learn the steps involved. The 2000 - 2005 Chevys do not have a chip in the key. You can go to Walmart and have duplicate made and they work fine if they are duplicated according to the new key you bought for the new cylinder. I hope this helps.

I just replace my ignition switch and lock cylinder on my 05 impala the lock cylinder came with two keys, I did the re programming steps numerous amounts of times but the security light still shows and my car won’t start anybody have any possible suggestions