# Data Provenance & Licensing This repository holds two free samples: the OBD-II sample (the CSV and Parquet files at the repository root) and the Heavy Duty (J1939) sample in `samples/heavyduty/`. The first three sections below cover the OBD-II sample; the Heavy Duty section covers the other. ## Code spine (dtc_code, short_description) - **Source:** https://github.com/Wal33D/dtc-database (generic SAE files `data/source-data/{p,b,c,u}_codes.txt`) - **License:** MIT. The MIT license permits commercial use, modification, and redistribution. A verbatim copy of the upstream license notice is committed in this repository at `LICENSE-upstream.txt`; attribution is provided here. - **Fetched:** 2026-07-06 via the MechanicDB build pipeline. - **Transformations applied:** filtered to SAE-controlled generic ranges (`P0`, `P2`, `P34x–P39x`, `C0`, `B0`, `U0`, `U3`), dropped `Reserved` placeholders, deduplicated, normalized linebreaks, derived `system_category` from the code letter. - **Underlying facts:** OBD-II code assignments and definitions originate in SAE J2012 / ISO 15031-6. Individual code-to-definition mappings are facts; facts are not subject to copyright. The SAE standard document text itself is NOT reproduced in this dataset. ## OEM code spine (oem_make, dtc_code, short_description) - **Source:** the same Wal33D/dtc-database compilation — 32 per-marque files, upstream MIT license at `LICENSE-upstream.txt`. This sample includes 15 of the full dataset's 6,637 OEM codes so the OEM columns are populated here too. - **Kept:** manufacturer-controlled ranges only (`P1`, `P30–P33`, `C1/C2`, `B1/B2`, `U1/U2`). Generic-range lines in brand files are dropped — the SAE spine above is the sole authority for generic ranges. - **Excluded:** `other_codes.txt` (definitions with no brand attribution — manufacturer-range codes are meaningless without the make). - **Badge engineering:** marques within an engineering group (GM's seven marques, Ford/Mercury/Lincoln, Honda/Acura, …) share most definitions; rows are kept per marque so make-filtered lookups work as buyers expect. ## Authored content (all other columns) `detailed_technical_explanation`, fault families, ranked fixes, difficulty ratings, cost/labor estimates, step-by-step instructions, and part mappings are original content authored for MechanicDB. Cost and labor figures are editorial estimates for typical aftermarket parts and independent-shop labor in the US market; they are not quotes. `probability_rank` is the supported legacy name for authored procedure consideration order, not measured cause likelihood. See the applicable `ordering_metadata.json` sidecar; the Heavy Duty sample's class-kind mapping is generated from the validated FMI policy. ## Heavy Duty sample (J1939) - **Files:** `samples/heavyduty/` — 100 fault rows from the MechanicDB Heavy Duty tier with their SPNs, ranked fixes, part mappings and the 32-row FMI register, in the same schema as the paid tier (DATA_DICTIONARY.md, section 6). - **Facts:** each SPN/FMI fault pair, OEM fault code (`oem_code`) and controller assignment is a fact taken from a fault-code document the manufacturer publishes. Every `j1939_faults` row names its document in `source_id`, `source_url` and `source_doc` (plus `source_page` where the document has pages); the documents are listed below. - **Authored content:** `short_description`, `spn_name`, `fmi_name`, `detailed_technical_explanation`, fault families, ranked fixes and part mappings are written in DataEngineered's own words. A `spn_name` may match the manufacturer's own plain name for the parameter (for example `Engine Coolant Temperature`); no sentences from OEM documents are included. Cost and labor figures are editorial estimates for US independent heavy-duty shops; they are not quotes and do not come from the OEM documents. - **Not SAE material:** nothing is taken from the SAE J1939 Digital Annex, J1939 DBC files, or third-party SPN/FMI tables derived from them. The 32 FMI names are our own paraphrase, not SAE text. ### Source documents The Heavy Duty tier is built from the documents below. The free sample holds rows from those marked *yes*; rows from the others are in the paid tier only. Sources added to or withdrawn from the tier are recorded in [CHANGELOG.md](CHANGELOG.md). | `source_id` | OEM | Controller | Document | URL | In free sample | | :--- | :--- | :--- | :--- | :--- | :---: | | `bendix_sd134869` | Bendix | ABS/ESC | SD-13-4869 EC-60 ABS/ATC/ESP service data sheet (2013) | | yes | | `bendix_sd134983` | Bendix | ABS/ESC | SD-13-4983 EC-80 ABS/ATC service data sheet (2014) | | yes | | `cat_c10882888` | Caterpillar | Engine ECU | 1200 Series marine auxiliary engines troubleshooting guide | | yes | | `cummins_a042j565` | Cummins | Engine ECU | A042J565 fire pump drive engine IOM, fault code charts | | yes | | `cummins_mddca` | Cummins | Engine ECU | Onan marine generator MDDCA operator manual | | yes | | `eaton_trts0950` | Eaton | Transmission | TRTS0950 Endurant HD fault code index | | yes | | `eaton_trts0960` | Eaton | Transmission | TRTS0960 Endurant XD fault code index | | yes | | `deere_omh229936` | John Deere | Engine ECU | OMH229936 9670/9770 STS engine control unit DTCs | | yes | | `deere_omrg35856` | John Deere | Engine ECU | OMRG35856 PowerTech DTC list | | yes | | `navistar_s082504` | Navistar | Body controller | s082504 Electrical System Troubleshooting Guide fault-code XML | | no | | `navistar_s08327` | Navistar | Body controller | S08327 Body Controller Diagnostic Trouble Codes (2010) | | yes | | `perkins_sebu8601` | Perkins | Engine ECU | SEBU8601-07 1206E-E70TTA industrial engine OMM, Table 3 diagnostic codes | | yes | | `psi_60l_obdhd` | PSI | Engine ECU | PSI 6.0L OBD-HD engine diagnostic manual (FCCC chassis) | | yes | | `wabco_mm0112` | WABCO | ABS/ESC | MM0112 ABS/ESC E-version maintenance manual (05.2020) | | yes | | `wabco_mm1719` | WABCO | ABS/ESC | MM1719 mBSP ABS/ESC maintenance manual (08.2018) | | yes | | `yanmar_over56kw` | Yanmar | Engine ECU, Aftertreatment DCU | Troubleshooting manual, engines over 56 kW (2024) | | yes | ## Dataset license Both free samples are offered under ODbL v1.0; the full databases are available under commercial license tiers (see README.md and the LICENSE file). ## Stable identity companions (since edition 2026.10) Existing code_id, fault_id, fix_id and part_id values are preserved by a committed allocation registry. IDs may be sparse and are scoped by domain/entity type. Use qualified references such as `mechanicdb:v1:obd:fix:571`; the same integer in HD or another table is a different identity. Numeric exports use permanent-ID order; procedure display remains ascending probability_rank (numeric CAST for Standard TEXT), with the existing I01 authored-order meaning. `identity_metadata.json` identifies the immutable data release and artifact; `identity_map.csv` / `.parquet` provide entitled references, decimal-text numeric aliases, parent references, authored keys and content revision digests; `identity_events.csv` provides relevant lifecycle information. The core SQLite schema is version 2. Public maps include only the authorized fixed samples. Text, rank and component-name changes preserve intended identity. Retired or withdrawn allocations are never reused; merge/split migration requires review. Historical integers require an exact artifact or verified source release. Two known September 2026 HD artifacts reused fault 571 for different entities; month and number alone are ambiguous. Migration reports preserve original targets and do not guess missing or changed historical procedure/part mappings. Paid editions carry these companions from 2026.10. Paid ZIPs carry the compact Parquet identity map; generated master directories and public samples provide both CSV and Parquet maps. Content revision detectors use the declared sha256-128 algorithm; full artifact/file/registry checksums use SHA-256. CSV consumers can convert the companion with pandas.read_parquet().