karsonmadden/us-vehicle-trouble-codes

US vehicle diagnostic trouble codes, linked to manufacturer bulletins and owner reports

1,142 OBD-II diagnostic trouble codes as they actually appear in US manufacturer service bulletins and NHTSA owner-complaint filings — with the model years, vehicle components and source documents each code shows up in.

Derived from public NHTSA filings. Regenerated nightly.

DOI: 10.5281/zenodo.22891283 — archived on Zenodo. That is the concept DOI: it always resolves to the newest version, which is the correct one to cite for a file that is rebuilt every night.

What this is, and what it is not

Code-definition dictionaries already exist, and most of them are copies of one another. This is the opposite direction. It does not tell you what P0420 means in the abstract; it tells you which real vehicles, which manufacturer bulletins and how many owner complaints that code actually turns up in.

Be clear about the limitation before you use it: only 119 of the 1,142 codes (10.4%) carry a plain-English meaning. If a definition lookup is what you need, this is the wrong dataset. The linkage is the value, and that linkage does not exist elsewhere as an open file.

Composition

code family	codes
P — powertrain	778
U — network / communication	147
B — body	131
C — chassis	86
total	1,142

Across the corpus those codes reference 128,336 bulletin occurrences and 5,434 owner reports.

Columns

column	meaning
code	the diagnostic trouble code, e.g. P0300
defined_by	standard where the code is SAE-standard, otherwise manufacturer-specific
meaning	plain-English definition where one is established — empty for ~90% of rows, see above
bulletins	number of manufacturer service-bulletin occurrences referencing this code
owner_reports	number of NHTSA owner complaints referencing this code
documents	number of distinct source documents
model_years	number of distinct model years the code appears against
components	pipe-separated NHTSA component categories, e.g. Engine And Engine Cooling|Power Train
page	canonical URL for the code on whichtrim.com

Files

• dtc.csv — 1,142 rows, 162 KB
• dtc.json — the same data with provenance: {generated_at, source, codes}

Provenance

Compiled from NHTSA's public bulk files (recall campaigns, manufacturer communications, owner complaints) by WhichTrim. Nothing is hand-edited; the files are regenerated nightly from the sources, so generated_at in the JSON is the authoritative timestamp for any given copy.

Live files, always current:

• https://whichtrim.com/data/dtc.csv
• https://whichtrim.com/data/dtc.json
• Landing page with schema.org Dataset markup: https://whichtrim.com/dtc/
• Permanent archive: https://doi.org/10.5281/zenodo.22891283

Licence

CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/

Use it commercially, redistribute it, build on it. Attribution required.

Citation

@dataset{whichtrim_dtc_2026,
  title     = {US vehicle diagnostic trouble codes linked to manufacturer bulletins and owner reports},
  author    = {{WhichTrim}},
  year      = {2026},
  publisher = {Zenodo},
  doi       = {10.5281/zenodo.22891283},
  url       = {https://doi.org/10.5281/zenodo.22891283},
  note      = {Derived from NHTSA public filings. CC BY 4.0. Regenerated nightly; this is the concept DOI and
               resolves to the current version.}
}

Plain text:

WhichTrim (2026). US vehicle diagnostic trouble codes linked to manufacturer bulletins and owner reports. https://doi.org/10.5281/zenodo.22891283

Related

The same project publishes a fuller vehicle record — recalls joined to severity and completion rates, owner complaints, NCAP crash ratings, driver-assist crash reports, EPA fuel economy and trim specifications — at whichtrim.com and through an MCP server registered as com.whichtrim/vehicle-records.

Three of those datasets are also CC BY 4.0 and can be used the same way as this one:

• the two files on this page, dtc.csv and dtc.json;
• driver-assist crash reports — every crash reported to NHTSA under Standing General Order 2021-01 with a Level 2 or automated-driving system engaged, joined to the model year it names: sgo.csv · sgo.json · landing page;
• the quarterly reports — a dated, frozen snapshot of a model year's federal recall record: /reports/, data.csv and data.json under each quarter.

Everything else — the full vehicle compilation, the per-vehicle JSON, the search index, the API and Recall Watch — is not CC BY. See the carve-out in the terms.