Diagnostic Tools

Start with the vehicle or trouble code, then use the guides to understand what to check next.

VIN Decoder

Enter a 17-character VIN to retrieve available vehicle details from the NHTSA database.

Search P, B, C, and U diagnostic trouble codes for meanings, symptoms, causes, and diagnostic steps.

Browse the complete code database by system category and open the guide for any listed code.

Learn what scanner features matter before choosing a basic reader or a more advanced diagnostic tool.