How to reset 2002 Trailblazer entry frequency (stolen key and fob)

Your owner's manual should tell you how to program new key fobs to the vehicle. If you don't have the owner's manual visit the website called just give me the damn manual. If they have it, it's a free download. Hope that helps! Jim

@Js08016 Please read question. That is not what was asked.

I did read your question. GM used a rolling frequency to synchronize the key fob to the vehicle. Each time the vehicle is locked or unlocked a different radio frequency is used. I believe there's 250 different frequencies. Once synchronized the vehicle computer knows what frequency will be transmitted next from your fob. If the expected frequency is not transmitted the computer will ignore it. Programming a new key fob or two new key fobs will cancel all old fobs. For example, if you want to program one new fob and keep one old fob both have to be programmed at the same time or the old one will stop working. The maximum number of fobs that can be programmed to the vehicle is two. Now if you're asking about the transponder ignition and door key, up to ten keys can be programmed to the vehicle. You can't delete keys yourself from the system. Your local Chevrolet Dealer has to do that. Even so, if someone has a key, they can still manually unlock the vehicle using the key. But if that key has been removed from the system it will no longer start the vehicle. So, to absolutely keep the person out of the vehicle you need new lock cylinders, new transponder keys, and the key fobs reprogrammed. A reputable locksmith can probably do all that for you but I'd trust the Chevy Dealer over a locksmith. Either way it won't be cheap! Hope that helps! Jim