* VIN (Vehicle Identification Number): This is the most crucial code. It's a unique 17-character alphanumeric identifier for your specific vehicle. You'll find this on a sticker on the driver's side dashboard (often visible through the windshield), and potentially a smaller version inside the glovebox or on the driver's side doorjamb.
* Tire and Loading Information: A sticker specifying tire size, inflation pressure, and vehicle weight limits. This is usually found on the driver's side doorjamb.
* RPO Codes (Regular Production Option Codes): These codes represent the options and features included on your specific Sierra. They can be found on a sticker, often located on the glove box door or in the owner's manual. Decoding these requires a GMC parts catalog or online decoder.
* Emission Control Information: Stickers detailing compliance with emissions standards. Location varies.
Therefore, instead of looking for a single "Vehicle Codes" sheet, check all the stickers and labels inside your glove box and on the driver's side doorjamb and dashboard. If you have the VIN, you can use it to find more detailed information about your vehicle's specifications online, such as through the GMC website or a third-party vehicle history service.
