Instant OBD-II Code Lookup
Decode any diagnostic trouble code. Search over 9,300 generic check engine codes instantly in your browser.
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Code Directory
Explore the complete database of 9,317 diagnostic trouble codes organized by system and subsystem.
Common Codes
Access detailed technical guides for the most frequently triggered check engine light codes.
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Diagnostic Glossary
Lookup vehicle acronyms, component definitions, and terminology (ECU, PCM, MAF, O2 Sensor).
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Understanding OBD-II Code Structure
Diagnostic Trouble Codes (DTCs) are standardized codes defined by the SAE J2012 and ISO 15031-6 standards. Every 5-character code is structured to convey specific diagnostic context:
- Character 1 (System): Tells you which primary vehicle system is reporting a fault: P (Powertrain), B (Body), C (Chassis), or U (Network/Communication).
- Character 2 (Type): Identifies whether the code is standard Generic (0 or 2) or automaker-defined Manufacturer-specific (1 or 3).
- Character 3 (Subsystem): For Powertrain (P) codes, defines the sub-assembly (e.g., fuel metering, ignition, auxiliary emissions, transmission).
- Characters 4–5 (Specific Fault): Represents the precise fault index identifying the malfunctioning circuit, component, or failure mode.
Authoritative Data. Simplified.
🔍 5-Character Visual Decode
Instantly dissect DTCs into their respective vehicle system, category, and subsystem parameters for immediate troubleshooting clarity.
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All diagnostic codes and explanations are structured using official standards (SAE J2012 / ISO 15031-6 / EPA OBD-II) with qualified mechanic references.
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