THE BASIC BREAKDOWN OF THE INFAMOUS "SECURITY LIGHT" ISSUE BY GM

The security light is a visual indication that something in the car's antitheft system is failing.  In most GM cars and trucks there is a hidden system that most people are unaware even exists. From the moment you put your key in the ignition, there begins a constant line of communication between your key's security chip or transponder, to the ignition's lock cylinder, and then to the car's TDM (Theft Deterrent Module). These 3 parts are in CONSTANT communication. If the key is in the ignition, then these parts are sending signals to each other. The security light illuminates when that signal gets broken, even just for a second. When the signal breaks, the car misinterperates this as an attempt at theft and goes into antitheft mode. The car thinks its being stolen or hotwired because it is not getting that signal from YOUR specific key. This is why the security light turns on and shuts down your vehicle. Remember too, the TDM controls the security light. Sometimes you can have ALL the symptoms and no lights.I have put this site together to help others out with this problem. Ive added things at different times so im sorry if the info is choppy or if there are things described twice. By no means am i a professional, i have just collected alot of info and put it on this page to help as many people as i can.

     MORE TECHNICAL "SECURITY LIGHT"                                    BREAKDOWN

1. The CHIPKEY Normally on older cars there is a black resister chip in key which "communicates" to the lock cylinder. Sometimes it is hidden in the plastic part of keys in new models. Same concept, might say PK3 or might have a "+" sign, a + with a circle around it, i've also seen 2 dots on some Saturns . .  The newer ones work on frequency and transponders. Same concept. The key sends a signal that is read by the ignition

2. The LOCK CYLINDER Inside the ignition lock cylinder there are pins that read the chip in the key OR the part that reads the frequency on newer models. So the key sends the signal, the ignition reads it and sends that info to the TDM.  Any break in this communication at startup, even for second can keep your vehicle from starting. 

There will be 2 ways further down to bypass and eliminate this aspect of the system. Both i have done, and both will work.

3. The TDM Theft Deterrant Module-Sometimes called the "computer" or "brain". This is the part that sends the signal to your car's starter or injectors and allows your car to start or continue running depending on your type of system. If any of these parts are not communicating properly, your SECURITY light will come on and shut down your vehicle. The idea being, that without the chipped key or frequency key communicating with the ignition, your TDM, and then to your starter or injectors, the vehicle wont start and can't be "hotwired" or stolen. Pretty nice when working, but these systems are flawed and the average life is 6-10 years. Tampering around with these parts can also cause problems. So many times i've heard of people changing the ignition, starter, or fuel pump and setting off the security system. I've also seen people try to change out these parts to try and fix the security. The concept being, if the key, ignition, and TDM don't match and communicate, the security will fail and shut you down. I've also noticed that weather can effect these things. Hot or cold days used to set my anti theft off ALL the time. Every single aspect of this system is expensive to replace and can only be worked on by "authorized" GM service men without voiding warrenty. Most garages don't even touch them and if they do, they will sell you every part they can before "fixing" the problem. If you have looked into replacement or fixing these systems, you know that the cost is very high and may actually be more than the Blue Book value of your vehicle. Lets face it, alot of us drive beaters. The Key and Lock Cylinder component ($350).The Theft Deterrent Module (TDM) or Body Control Module (BCM)(aka the Brain of the system – $700)The wiring between #1 and #2 Plus anything else the dealer can and WILL try to sell you. Starters, batteries, injectors, fuel pumps, selenoids, keys, ignitions, LABOR and so on.

                             SYMPTOMS

          Symptoms of a Security system failure. This is for any GM vehicle with a Passlock,                                                  PASSkey,or Vats antitheft security systems.

1) A light saying SECURITY or ANTITHEFT is illuminated solid or flashing

2) A light shaped like a car with a "padlock" through it is on or flashing.

3) The vehicle will not start. The starter will not even click and everything else in the car will work fine. Security light will be on most of the time.

4) The engine will start for 1-5 seconds and then stall, followed by a security light.

             MY FIRST ENCOUNTER WITH THE                               "SECURITY LIGHT"
I had crashed my 2001 Cavalier into a snowplow so i bought a car from an "acquaintance" very cheap. 1000 bucks for a 96 Regal with a ton of miles, but should get me through the winter. First i started notice intermittent starts. It would act up one day, then be fine for weeks. Run great for a few months, then would not start when i needed my car the most. This only got worse and more often. I thought i could just keep doing that 10 minute key trick (described below) forever, but NO. (i did do it for the better part of a year though) The final straw for me was when i had my daughter in the car (5 years old at the time) leaving a Walmart, it was a below freezing Illinois winter and the thing would not start. Having to tell her that we have to run in the cold and ice to go back inside and wait ten minutes for my car to start was heart breaking and embarrassing. She did not understand. I then decided to get this fixed. Every place i took my car to was talking about $600-$900 for a TDM replacement. I knew there had to be a cheaper way. And of course there IS. 
 

                      *QUICK FIX TRICKS*
1st trick: Try a spare key that is newer or used less. The pins wear down with use and so do the keys causing the security to fail. Transponders can get damages or lose power and fail as well.

2nd trick: (10 minute trick if not starting) Turn the key forward 2 clicks until right before it would normally start, leave like that for 10 minutes. ( no less ) After 10 minutes, turn key back then forward and your car might start. I did this in my Buick for more than a year. If its shutting down while running, I'm sorry I have no quick fix...

Note: If you can see the little black chip in your key shaft, then you have a Vats system. If the ten minute trick works on this system, then the problem is NOT in your key or ignition. It is the TDM itself. It will have to be fully bypassed or a new TDM installed. This system does not relearn or reteach the ignition like the Passlock and Passkey systems do that came after them..

                                                    *TEMPORARY FIX*

                                                                    (Only ignition and key bypassed)

I used to have a link to a webpage here, but the owner of the page requested that i remove his link. So i will give you a basic rundown from my knowledge. On the VATS system's ignition cylinder is an orange or yellow wire coming off the housing. Inside the Orange/Yellow shielding are two white wires. 

These wires are what read the OHMS of the chip in your key. So basically you can take an OHM meter and read the OHMS between the sides of the chip in your key. Whatever the reading is (one of the 15 listed below) you can reproduce this with simple resisters from Radio Shack or some place like that. You place your resister pack between these 2 white wires, and you've now bypassed the ignition and key. This is an inexpensive way to do this, and it can work well, but i strongly recommend only using it for a short time. I did this in my Regal and got stranded not long after with a hefty tow bill. The system isn't designed to read that constant signal and you can kill your Theft Deterrent Module even faster. I've heard horror stories of clipping the wrong wire and getting the airbag instead. Be sure the wires are coming from the ignition. I've also heard stories of cutting a wire behind the radio and just leaving it. Honestly this can't be a good idea. If you could bypass the system simply by cutting one wire... they wouldn't even be putting them in anymore.

Remember that this only bypasses the KEY portion of the SECURITY system. If the Theft Deterrent Module is bad, this will not work. If you have a Passlock or Passkey 3 system, this will not work either. This is strictly for the VATS system The only known system i have found to bypass VATS, Passkey, and Passlock... Is the NEWROCKIES bypass module listed below. I have now installed 3 of these on personal vehicles. I just did my 1990 Olds Toronado Trofeo,small video proving the security system is bypassed, and some install pictures up in the gallery.

                     PERMANENT SOLUTION

                                                          (everything bypassed. Ignition,key,and TDM)

Well since the lifespan of these systems are so short, and are extremely expensive to fix, my only permanent suggestion is to eliminate it completely. After a year of doing the 10 minute "Quick Fix" and a "key bypass" that lasted 2 months and stranded me, i have only one good suggestion. After surfing the web for hours through forums and websites and paying for parts that i didn't need, i found this link on Fixya.com from another random guy like me.

                                http://newrockies.com/

Save this link to your favorites. --------^ You will probably end up needing it sooner or later. They sell a Pro Bypass Module that eliminates the chip, the lock cylinder and the TDM. That's EVERY part of the system. As far as i know, this is the only one that bypasses every part of the system. There are a lot of bypass systems out there, but they are designed to work with remotes starters and will still rely on the security system once you insert the key. This is the only one i found that is designed to fix the failure, and not just get thr car to temporarily start on a cold morning.  Supposedly It replicates the signal from the TDM and sends it directly to the computer and then to the starter or injectors and so on. Thus eliminating the ENTIRE system COMPLETELY. I came upon a fork in my road. A TDM that costs $700 for my $1000 car, or spend the $250 for this bypass, or just throw my car away. Lets say i now drive a Buick with the chip ripped out of the key and the TDM sitting in my glove box for "show and tell". No problems since. I just told myself "I'm not spending 250 bucks, i'm saving a 1000 bucks". 

                                                                                     ^----- I copied this picture off of their Facebook

There is a list of known effected cars that can be fixed with the Newrockies bypass at the bottom of this screen. This is the same list from their site and may update. Double check the list on the site before you get too excited. If you don't think you can install this part on your own, remember you can always ask your mechanic to help. When i did this on my Buick, it took me about 30 minutes to find the TDM and about 10 minutes to install the part. I am not a mechanic. Just an average handy guy.  I had no idea what i was looking for, you now have 3 pictures. In my Olds, mine looked like this top picture, only grey in color with the same sticker. It says PASS-Key on it. 

  VATS CHIP VALUE CHART

 Some Videos & Links Worth Seeing:

PICTURE GALLERY ON THIS WEBSITE

NEWROCKIES PRO MODULE IN ACTION

HOW TO MEASURE VATS KEY VALUE

INSTALL A NEWROCKIES PRO MODULE

INSTALLATION  WALK THROUGH. NEWROCKIES PRO MODULE 

Yes i know this is a FORD key, but it was the only picture i could find showing the cutaway.

BYPASS GM'S ANTI THEFT SECURITY SYSTEM ALL BY YOURSELF. DON'T PAY THE DEALER $1000 TO FIX THE PROBLEM THAT THEY SOLD TO YOU IN THE FIRST PLACE.