If you own a 98-02 Chevy Fullsize Truck or SUV(C and K series GMT-400), Savanna or Express van, or a 98-99 GMC Safari or Chevy Astro, your vehicle is equipped with a component called a "Passlock Module".
It has many names including Anti-theft module, VATS module, Passlock, but they all refer to the same part. This components job is to tell the ECM that the correct key is being used to start the vehicle. When this part fails you'll have several common symptoms. The most obvious being that the car will crank but not start. This symptom by itself doesn't necessarily point to the Passlock module as the culprit. If you notice your "security" light is illuminated in your instrument cluster, along with a no-start, it usually means you have a faulty passlock module. If your security light blinks, you may have a damaged key or passlock sensor in your ignition switch.
Since 2015, These modules have been OBSOLETE from GM. You cannot buy them new. We have now teamed up with Pro-Rebuild, who has designed and built a tester using proprietary software and hardware to ensure that every single passlock module they sell tested good both before and after the rebuilding process. I would NEVER trust a USED module as most of them are BAD. They use the highest quality components to guarantee these modules will outlast your truck. All of their passlock modules carry a LIFETIME WARRANTY. They also offer $25 off of your initial purchase price when they receive your old module back.
There are 6 different part numbers. Most of them run $149.99 including shipping to any US Zip Code. Those part numbers include: 16264955, 16264975, 16264985, 09352885, 16265005. The part number 16264965 is $199.99. For any questions feel free to call Pro-Rebuild at 573-340-3776. You can view and purchase on their ebay page here.