I am completely overhauling this initial post so that people can understand what this thread is about...
There IS a fix if you have had or currently are experiencing problems with your car not starting because of the "Security" light coming on. This will even deal with what you can do to possibly start your car so that you can fix the problem. (Note: that might not always work in some cases.)
The following instructions are written SPECIFICALLY for a Chevy Impala that use the Passlock II system.
HOWEVER, these instructions are good for
ALL GM vehicles, the only difference is that the diagrams will probably be slightly different.
This thread will also deal with what to do if you are experiencing "weird" strobing or flashing lights in your car at random times. Some people have also experienced the following symptoms:
-Random lights flashing on and off.
-Traction control light turning on and off randomly.
-Power windows / Power locks not working randomly.
-Lights inside the car flickering.
-Fog lights turning on and off by themselves.
-Hearing "clicking" sounds by the fuse box in conjunction with random lights.
I will try and have kind of a running
wiki in this first post to help people with getting into the specific post that they need for the problem they're having.
What to do if you're having problems with the security light coming on, but your car still runs fine.
What to do if you're having problems with the security light coming on AND your car does not start, or does not start intermittently.
1)
First, try the SECURITY RELEARN PROCEDURE in this link
2)
If above does not work, try this - clean out your ignition switch.
3)If cleaning out your ignition switch does not work, you may have to do the following - in some cases possibly ALL THREE:
a) Do the "
Bypass Method". (Thanks to Ponchonutty)
b) Replace your ignition cylinder.
Here is a quick guide on how you can do this yourself. (Just a quick FYI if you're going to replace your own ignition cylinder).
c) If you have an aftermarket alarm system (ie. remote start)... You will probably have to remove the entire board and RESPLICE the wiring correctly.
For those attempting to do the above themselves this
diagram shows you a picture of all the wires and how remote starts generally work. Do this ONLY if you know what you're doing.
4) If you've done ALL of the above - and it still doesn't work, I recommend changing your BCM.
Here is a picture of a BCM on an Impala - and the post will also tell you where to get to it to replace it. (Thanks to HeMi101)
(A WORD OF CAUTION ON REPLACING YOUR BCM: Since the new BCM has to be programmed with the new BCM already installed in the vehicle - you will not be able to install the new BCM and drive it. It will have to be programmed before your car will start)
If you are having weird issues with you car, like the automatic doors/windows won't work. Lights flickering, etc.. More than likely, your BCM is bad or going bad. Do option number 4 above.
Good Luck, and I hope this helps people.