A 2003 Silverado may have a key with a chip. The key with the chip is called the PASS-Key III+. The PASS-Key III+ system was introduced in 1998 and was used on all GM vehicles until 2005. The PASS-Key III+ system uses a transponder chip in the key to communicate with the vehicle's immobilizer system. The immobilizer system will only allow the vehicle to start if it recognizes the correct transponder chip.
