Bimmer VIN Decoder

Purpose & User Intent: The Bimmer VIN Decoder interprets 17-character VINs to identify BMW vehicles. Target audience includes technicians, parts specialists, insurers, used-car dealers, and enthusiasts who need rapid identification for diagnostics, compatibility checks, and service planning. It resolves make, country, model line, body style, engine code, drivetrain, model year, plant, and option codes.
Core Logic & Features: Required features include VIN validation (length 17, disallowed letters I,O,Q), ISO 3779 check-digit calculation, and WMI inference for Germany. It provides VDS-based decoding for model year, plant, and option codes and supports BMW-specific model-code lookups when available. Optional: cached year-model mappings, advanced compatibility flags, and export-ready JSON for downstream systems.
Inputs & Outputs: Input is vin (string, 17 chars). Output includes manufacturer, country, model line, model year, body style, engine code, plant, serial codes, and option_codes when available. Formatting is uppercase for integration.
Algorithms & Calculations: Uses transliteration of VIN characters and position weights per ISO 3779 to compute the check digit; if valid, vin_valid is true. Year code cycles every 30 years; mapping to a specific year requires context. BMW-specific mappings are used when available.
Error & Edge Cases: Invalid length or disallowed characters set vin_valid to false; check-digit mismatch yields invalid validation for dependent fields. Unknown WMI yields partial decoding with BMW descriptors. Ambiguous year codes return plausible year ranges; data unavailability yields partial results.
Industry/Region & Localization: Follows ISO 3779 with regional production nuances; outputs in English; year decoding follows standard codes used in major markets.
Assumptions & Exclusions: Assumes access to authoritative WMI and model-code data; does not perform owner history checks or full factory option decoding beyond common codes; not a substitute for official vehicle records.