GM has first used transponder chip keys in 1997, but were slow to phase the technology in. Today, GM uses transponders on most of their models. Do not confuse transponder chip keys with the earlier VATS/PASS keys which contain a visible resistor pellet. Most GM original transponder chip keys have either a PK3, PK3+ or just a "+" stamped on them. GM also uses a technology called Pass Lock on some cars from 1996 to 2007. These cars do use electronics in conjunction with the ignition lock, but there are no electronics in the key. This is often a point of confusion.
Another common misunderstanding are immobilization technologies used on trucks. GM did not use transponders on any trucks until 2007.
