4AU versus another similar code on Chevrolet Equinox

What is a GM build sheet?

A build sheet is General Motors' own factory assembly record for a specific VIN. It lists the RPO (Regular Production Option) codes the vehicle was built with — every package, individual option, paint and trim selection, axle ratio, and equipment group — exactly as it left the plant.

Where a window sticker is written for the buyer with plain descriptions and pricing, the build sheet is the underlying code-level truth. It's the most reliable way to confirm how a used Chevrolet, Buick, Cadillac, or GMC was originally configured, long after the original paperwork is gone.

Window sticker vs. build sheet

Newer GM vehicles (roughly 2020 and later) usually have the original window sticker PDF on file — the Monroney label with standard and optional equipment, fuel economy, warranty, and the full MSRP breakdown.

When a window sticker isn't on file, this tool automatically falls back to the build sheet: the list of RPO codes with their descriptions. Either way you come away with the factory record of how the vehicle was equipped.

RPO codes explained

Every factory option on a GM vehicle has a three-character RPO code — for example a specific paint, a tow package, a sunroof, or an audio system. These codes are also printed on the label inside the glovebox or spare-tire well.

The build sheet pairs each code with a readable description, so you can translate a glovebox full of codes into the actual packages and features the vehicle carries. That makes it easy to verify a seller's claims or settle exactly which options are factory.

4AU versus another similar code on Chevrolet Equinox

Exterior & Appearance · 2021 Chevrolet Equinox · 294 views · 0 replies

4AU — Primary exterior color: Silver Lightning, Metallic 2. This code identifies the vehicle's factory-applied main exterior paint color. Browse RPO codes →

Nathan B. Sep 5, 2025 · Florida

Two similar Chevrolet Equinox build sheets use different codes for what appears to be the same feature. Mine uses 4AU, described as “Primary exterior color: Silver Lightning, Metallic 2. This code identifies the vehicle's factory-applied main exterior paint color” Can anyone explain how these variations are normally handled?

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