Understanding VW Factory M-Codes
M-codes are Volkswagen’s internal factory option codes. Every aircooled VW left the factory with a set of M-codes defining its exact equipment, regional specification, and special features.
What Are M-Codes?
An M-code is a numeric code (typically M-followed by a number, such as M213 or M559) that specifies a particular option or specification. These codes covered everything from engine specifications and transmission type to export market adaptations, color/trim combinations, and accessories.
Think of M-codes as the factory’s recipe for building your specific car. Two Beetles from the same year could have very different M-code strings, indicating different markets, equipment levels, and specifications.
Where to Find M-Codes
- Factory data sticker: Usually located in the luggage compartment lid or glove box. Lists chassis number, paint code, and M-code string.
- Build sheet / production card: If your car retains its original paperwork, the build sheet lists every M-code assigned at the factory.
- VIN plate: Some later models include select M-code information on the VIN data plate.
Common M-Code Categories
Engine / Drivetrain
Engine displacement, compression ratio, transmission type, gear ratios
Regional / Market
Export specifications, country-specific equipment, lighting, bumpers
Body / Color
Paint code, upholstery, trim level, sunroof, cabriolet top
Accessories
Radio, heater upgrades, seat belts, mirrors, bumper guards
How to Use the M-Code Archive
The Aircooled Index M-code archive contains 668 documented codes. You can search by code number, description, platform (Beetle, Bus, Type 3, Ghia), or category. When decoding a chassis, the decoder will automatically cross-reference any M-codes associated with your vehicle’s specification.
Browse the M-Code Archive
Search all 668 documented factory option codes.
Open M-Code Archive