You’re likely one of the thousands of General Motor vehicle owners that are struggling to start your car due to a problem with your vehicle’s anti-theft system. Unfortunately, this is all too common with Chevy, Buick, Oldsmobile, etc. cars and trucks and can be frustrating and expensive to fix. To give you some background, I had a 2000 Chevrolet Tahoe that left my wife and daughter stranded several times in the parking lot at Wal-Mart or school. In addition to being embarrassing, it was dangerous and I just didn’t want to deal with it anymore. I took (beautiful) Tahoe to the dealership for diagnosis, and they told me it could be many things – ranging from the body control module to computer or the ignition switch. $180 later they said it was fixed, but the security light went off again a few days later. The next “fix” from them would cost $950, and because they had to “order the part,” there was no return or refund if it didn’t fix the problem. I decided to just bypass the entire darn thing.
Bypassing GM’s Vehicle Anti-Theft System
- Databus All Combo Bypass and Door Lock Module
- Covers over 95% of cars on the road today
- Supports legacy systems like VATS and PASSLOCK
- Supports doorlocks and override on cars like Toyota with pushstart ignition systems and Chrysler with electronic ignition
I’m a pretty handy guy (and I’m cheap) so I first tried to wire in a resistor using some tutorial I found on the net. I’ll save you from the boring story, needless to say it didn’t work. I tried everything. I even changed the ignition switch twice. Still didn’t work. Was there something wrong with the wiring? Was the resistance of this boogeyman-made electrical system changing for some reason, like corrosion or a bad connection? I dunno, but I was tired and frustrated. So I bought a module to bypass the entire system . That worked so well, it blew my mind. Honestly, that’s the reason I wrote this blog. I spent literally dozens of hours troubleshooting and reading articles online and watching videos, and in the end it only took me about an hour to pop this little sucker in and hook it up. In case you want more info, keep on reading, otherwise just go to Amazon and get the Directed Electronics XpressKit DBALL2 Databus All Combo Bypass Module , it really works.
Understanding the GM Anti-Theft System
The VATS system (which stands for vehicle anti-theft system) is usually just called PassKey. Since debuting in the 1985 Chevy Corvette, it was used in other models and went through several iterations, including PassKeyII and PassKeyII, and PassLock. Passlock is a little different, as it doesn’t use a resistor pellet, but it essentially works the same otherwise.
How The VATS PassKey/PassLock System Works
So if you haven’t noticed, your ignition key has a little chip embedded into the side of it. Well, it’s not really a chip, it’s actually a resistor pellet. There are over a dozen different resistances used by General Motors, I suppose the thought here was that a prospective thief wouldn’t likely have the exact resistance on hand. These keys are paired to a special ignition lock cylinder. Turning the ignition key sends a signal to the VATS module that reads the resistance of the contacts in the lock cylinder and related wiring (this related wiring is one place where problems can occur). Then, depending on the reading, the system will output one of three modes: tamper, normal, and fail enable. You can read more about the modes here. These three modes determine whether your car starts up, or whether you’re stranded.