Data Methodology

Primary Data Sources

• OBD-II standards: SAE J2012 and ISO 15031-6 define the master list of generic Pxxxx, Bxxxx, Cxxxx, and Uxxxx codes. We parse the published standard tables to extract code numbers, short names, and system ownership.

• Technical Service Bulletins (TSBs): Manufacturer-issued TSBs refine cause and action data beyond the generic standard. We monitor NHTSA's public TSB database and cross-reference with ALLDATA and Mitchell 1 where accessible.

• Tesla alert codes: Tesla's internal diagnostic system uses a proprietary string-based code format (e.g., BMS_a001). The dictionary on this site is derived from community-maintained firmware analysis and is not an official Tesla publication.

• Manufacturer-specific codes: P1xxx–P3xxx (manufacturer-defined ranges) are sourced from OEM workshop manuals, publicly available repair databases, and community-verified reports.

Validation Process

Each code definition passes through three checks: (1) cross-reference with the primary standard, (2) consistency check against at least one secondary source (workshop manual or TSB), and (3) editorial review for clarity and safety accuracy. Severity ratings (critical / warning / caution / info) follow the SAE J2012 fault type taxonomy.

Translation Process

English definitions are the source of truth. Translations into German, French, Spanish, Dutch, Portuguese, Turkish, Norwegian, Korean, and Chinese are produced with machine assistance using a style guide that prioritises technical precision over idiomatic fluency. All translations are reviewed for accuracy before publication. Machine-translated content is marked in the data layer.

Review Cadence

The full dataset is audited quarterly. High-traffic pages (top 500 by sessions) are reviewed monthly. When a manufacturer issues a TSB that changes cause or action guidance for an existing code, the affected page is updated within 30 days.