About the data
OBD2DTC is an independent reference. Nothing here is sold, and the site is not affiliated with any vehicle maker.
Where the numbers come from
| What | Source | Licence |
|---|---|---|
| Meaning, causes, symptoms, repair estimates of 9,533 generic codes | OBDex — independently written descriptions, not SAE text | CC0 |
| "What to check first" notes for 142 common codes | Written for this site | — |
| Owner complaints: counts per model year, systems, codes mentioned, crashes, fires, injuries | NHTSA complaints database | US public domain |
| Engines and transmissions per model year | fueleconomy.gov (US EPA / DOE) | US public domain |
| Škoda and Renault model lists | Wikidata | CC0 |
How the owner numbers are made
For each brand, model and model year from 2012 to 2025 we take every complaint owners filed with NHTSA (159,571 complaints, 230 models). A complaint lists the systems involved; we count those. If the owner's text quotes a trouble code, the code is counted once for that complaint. Manufacturer codes are shown only when at least two complaints quote them. We store the counts only, never the owners' texts.
The data covers vehicles sold in the United States. Models sold only in Europe have no NHTSA complaints. A higher count can mean more cars on the road, not only more faults.