GM RPO Codes: How to Find a Chevy or GMC's Factory Options From the VIN

The fastest way to see a Chevy, GMC, Buick, or Cadillac's factory options is to read its RPO codes, the three-character Regular Production Option codes GM assigns to every engine, axle, package, and paint choice. On older GM vehicles they're printed on the Service Parts Identification (SPID) label, usually in the glovebox. On 2018 and newer models, GM moved that same data into a QR code on the certification label on the driver-side door pillar. A free VIN decoder won't give you the full list, which is why so many listings get the tow package or axle ratio wrong.

One wrong option on a used half-ton can swing the price by more than a set of tires, and the classic November 2026 version of this goes like so. A listing says "max tow," the photos are blurry, and the seller swears it has the locker. Reading the codes takes two minutes and settles that before you've driven across town.

What an RPO code is and why it beats the listing

GM builds each vehicle from an order made up of option codes. Each code is three characters, letters and numbers, and together they describe what the truck actually left the factory with. GM's own TechLink newsletter describes the SPID label as listing the VIN, the RPO codes, and other information that identifies the content of the vehicle.

You'll see these codes in GM's official paperwork too. When GM filed its 2025 engine recall with NHTSA, it identified the affected trucks by the 6.2L V8 "RPO L87." That's how precise the system is. A dealer advertising "6.2" on a truck that actually has the 5.3L is either careless or hoping you won't look, and the RPO list ends that conversation.

Where to find the codes on the vehicle

On most GM vehicles before the 2018 model year, open the glovebox and look on the inside of the door or the inner wall for a paper sticker with rows of three-character codes. GM's TechLink notes the SPID label has often been located in the trunk or glovebox, so check under the trunk floor or on the spare-tire cover if the glovebox is bare.

Starting with the 2018 model year, GM said much of the SPID information would be available through a QR code on the certification label on all Buick, Cadillac, Chevrolet, and GMC models, phased in over several months. That label is on the driver-side B-pillar on every GM model except the Corvette, where it's on the driver's door. Scan it with any QR reader on your phone. GM's newsletter says the scan returns the VIN, model year, model, build month and year, vehicle order number, the RPO codes sorted alphanumerically, and the paint code. Up to 48 RPO codes may be displayed.

Check the VIN on the label first

This is the step people skip. The VIN in the RPO data should match the windshield VIN and the title exactly. Glovebox doors get swapped in junkyard repairs, and a SPID sticker from a different truck will happily tell you about options this one doesn't have. If the VIN doesn't match, ignore the label and lean on the QR code or dealer records. If nothing matches anywhere, slow down and read our post on VIN decoders that show the wrong trim, because a mismatch can be a paperwork problem or something worse.

Why a free VIN decoder doesn't give you RPOs

A VIN encodes the basics: maker, body, engine family, model year, plant. NHTSA's vPIC decoder lets you query a VIN to identify the information encoded in the number, including the plant of manufacture. Packages like a trailering setup, a specific axle ratio, or a locking differential generally aren't encoded in the 17 characters. That's why a decoder can confirm a 2021 Silverado 1500 crew cab and still leave you guessing about the axle. Our Chevrolet VIN decoder guide and GMC VIN decoder guide show what each position does tell you.

The other routes to the full option list are a GM dealer's parts or service desk, who can pull the build data by VIN, and the original window sticker if it still exists. Our post on window sticker lookup by VIN covers that path.

Reading the codes without getting fooled

• Read the whole list. Most codes are routine: emissions, radio, labels, standard equipment. The handful that matter for value are engine, transmission, axle, trailering, and package codes.
• Decode against the model year. Look each code up in a reference for that exact year and model rather than trusting a forum list from a different generation. GM's TechLink says RPO descriptions are in the service information under General Information, which is what dealer techs use.
• Match codes to hardware. If the codes say a trailering package, look for the hitch receiver and the wiring. If they say a locking rear diff, ask the seller to show you, or check the axle tag. Codes tell you how it was built. Parts can be removed after.
• Tie it to the tow rating. Axle ratio and trailering codes change what a truck is rated to pull. See our guide to towing capacity and GVWR on a used truck before you hitch anything heavy.

Codes tell you the build, a report tells you the life

So once the options check out, you still need to know what happened to the truck after the factory. A max-tow package is also a hint the truck may have worked hard, and RPO codes can't tell you about a frame repair or a salvage title. That part comes from a history report. We sell licensed CARFAX and AutoCheck reports and aren't connected to CARFAX, AutoCheck, or Experian; none of them is free. Buying direct, the usual price is $39.99 to $44.99. With us it has been about $5.50 for a guest, $4.50 or so for members, and roughly $6.75 for a CARFAX-plus-AutoCheck bundle. Confirm at checkout. If a seller insists their "dealer printout" is all you need, ask yourself why they'd rather you didn't run your own.

Sources

• GM TechLink (Mid-May 2017): SPID label content now included with certification label
• NHTSA vPIC VIN decoder
• NHTSA: GM recall report 25V-274, identifying trucks by RPO L87