official
Standards bodies and official product documentation. Highest weight for diagnostic claims.
Sources
Diagnostic terminology on this site is grounded in U.S. federal regulations, SAE J1939 standards, EPA guidance, and OEM technical documentation — not forum posts or unverified secondary material.
Where the Data Comes From
Every indexed page must be tied to at least one source from the registry below. The primary sources used across this site are:
- FMCSA (Federal Motor Carrier Safety Administration) — ELD malfunction categories, hours-of-service compliance, and braking system standards
- Electronic Code of Federal Regulations (eCFR) — 49 CFR Part 395 and related regulations, updated continuously by the National Archives
- SAE International — J1939 Standards Collection — the SPN/FMI framework and J1939 protocol definitions that underpin modern heavy-duty diagnostics
- U.S. Environmental Protection Agency — heavy-duty engine emissions context and regulated system overview
- OEM technical documentation — manufacturer-published service documents from Cummins, Detroit Diesel, Bendix, WABCO, and others
Secondary and industry sources are used only where primary sources are unavailable, and are marked accordingly in the registry. See the methodology page for how sources are classified and applied.
Source Quality Tiers
government
FMCSA, eCFR, NHTSA, EPA. Authoritative for regulatory and safety context.
OEM
Manufacturer service information, bulletins, or public technical documents. Used for model-specific claims.
industry
Reputable training, fleet, or supplier sources. Used with caution and cross-checked where possible.
secondary
Non-primary material. Used only when cross-checkable against a primary source.
unverified
Lead discovery only. Cannot support any indexed diagnostic claim.
Primary Source Registry
ELD Malfunctions and Data Diagnostic Events
Federal Motor Carrier Safety Administration · government · confidence high · accessed 2026-05-05
Used to verify ELD malfunction and data diagnostic categories and high-level compliance actions. Do not copy guidance text verbatim.
View source ↗49 CFR 395.34 - ELD malfunctions and data diagnostic events
Electronic Code of Federal Regulations · government · confidence high · accessed 2026-05-05
Used for legal context around driver and motor carrier responsibilities. Verify current regulation before compliance decisions.
View source ↗49 CFR Part 395 Appendix A to Subpart B - Functional Specifications for ELDs
Electronic Code of Federal Regulations · government · confidence high · accessed 2026-05-05
Used to verify ELD self-monitoring categories and functional context. Summaries are original and conservative.
View source ↗49 CFR Part 393 - Parts and Accessories Necessary for Safe Operation
Electronic Code of Federal Regulations · government · confidence high · accessed 2026-05-05
Used for conservative safety context around commercial vehicle systems. This site does not provide legal advice.
View source ↗Bendix EC-60 ABS/ATC/ESP Controllers Service Data SD-13-4869
Bendix Commercial Vehicle Systems, hosted in NHTSA Manufacturer Communications · oem · confidence high · accessed 2026-05-05
Used for factual Bendix EC-60 UDS, blink-code, J1587, and J1939 SPN/FMI mappings. This site does not copy troubleshooting procedures.
View source ↗NHTSA Manufacturer Communications Search
National Highway Traffic Safety Administration · government · confidence high · accessed 2026-05-05
Used as a government-hosted discovery path for manufacturer communications. Individual fault-code pages should cite the specific document used, not this broad search page alone.
View source ↗WABCO ABS and E Version Hydraulic ABS Maintenance Manual MM-0112
WABCO / ZF Commercial Vehicle Solutions · oem · confidence high · accessed 2026-05-05
Used for factual WABCO ABS/ESC SPN, SID, FMI, and component mappings. Diagnostic procedures are not copied.
View source ↗WABCO mBSP ABS / ESC Maintenance Manual MM-1719
WABCO / ZF Commercial Vehicle Solutions, hosted in NHTSA Manufacturer Communications · oem · confidence high · accessed 2026-05-05
Registered as a trusted WABCO ABS/ESC source for future extraction. Do not copy diagnostic text or procedures verbatim.
View source ↗WABCO RSSplus Trailer ABS Maintenance Manual MM-0888
WABCO / ZF Commercial Vehicle Solutions · oem · confidence high · accessed 2026-05-05
Used for factual WABCO RSSplus trailer ABS SID/FMI and suspect-component mappings. Diagnostic procedures are not copied.
View source ↗Bendix EC-60 Advanced Controllers Service Data SD-13-4869
Bendix Commercial Vehicle Systems, hosted in NHTSA Manufacturer Communications · oem · confidence high · accessed 2026-05-05
Registered as a Bendix EC-60 source for cross-checking. Use factual code mappings only and do not copy service text.
View source ↗Navistar Body Controller Diagnostic Trouble Codes S08327
Navistar / International Truck Body Builder · oem · confidence high · accessed 2026-05-05
Registered for body-controller DTC extraction. This run did not publish pages from the PDF because text extraction needs additional normalization.
View source ↗Navistar Aware Vehicle Intelligence Diagnostic Trouble Codes S08312
Navistar / International Truck Body Builder · oem · confidence high · accessed 2026-05-05
Used for factual SPN, FMI, message, comment, and probable-cause fields from the public XML table. Summaries are original and conservative.
View source ↗Supporting Source Registry
SAE J1939 Standards Collection
SAE International · official · confidence medium · accessed 2026-05-05
Used only as a pointer to the official standards family; this site does not reproduce SAE standard text.
View source ↗Cleaner Trucks Initiative and Heavy-Duty Engine Emissions Context
United States Environmental Protection Agency · government · confidence medium · accessed 2026-05-05
Used for high-level educational context about regulated heavy-duty diesel emissions systems. Do not use for model-specific repair claims.
View source ↗QuickServe Online
Cummins Inc. · oem · confidence medium · accessed 2026-05-05
Used only to identify Cummins official service information as an authoritative verification path. No diagnostic text is copied.
View source ↗DiagnosticLink
Detroit Diesel Corporation · oem · confidence medium · accessed 2026-05-05
Used only for general context that Detroit and DTNA service information should be used for final diagnosis.
View source ↗Bendix ACom PRO Diagnostic Software
Bendix Commercial Vehicle Systems · oem · confidence medium · accessed 2026-05-05
Used only for Bendix ABS and safety-system diagnostic-tool context. No service procedure text is copied.
View source ↗Bendix EC-60 Standard / Premium Controllers Service Data SD-13-4863
Bendix Commercial Vehicle Systems · oem · confidence medium · accessed 2026-05-05
Registered for future Bendix EC-60 standard and premium controller cross-checking. Do not copy service procedures.
View source ↗Bendix EC-80 ABS / ATC Controllers Service Data SD-13-4983
Bendix Commercial Vehicle Systems · oem · confidence medium · accessed 2026-05-05
Registered for future EC-80 ABS/ATC data extraction. Factual mappings require source confirmation before publishing.
View source ↗Bendix ESP EC-80 Controller Service Data SD-13-4986
Bendix Commercial Vehicle Systems · oem · confidence medium · accessed 2026-05-05
Registered for future Bendix ESP EC-80 extraction. Use only factual mappings and conservative summaries.
View source ↗Eaton Gen 3 AutoShift / UltraShift Troubleshooting Guide TRTS0930
Eaton · oem · confidence medium · accessed 2026-05-05
Registered for future Eaton transmission fault-code extraction. Do not publish code mappings until the source table is extracted and checked.
View source ↗Eaton UltraShift PLUS Troubleshooting Guide TRTS0940
Eaton · oem · confidence medium · accessed 2026-05-05
Registered for future UltraShift PLUS extraction. Do not copy troubleshooting procedures or publish unchecked mappings.
View source ↗Eaton Endurant HD Troubleshooting Guide TRTS0950
Eaton · oem · confidence medium · accessed 2026-05-05
Registered for future Endurant extraction. The PDF download timed out during this run, so no indexable code pages were generated from it.
View source ↗Eaton Roadranger Warranty Repair Guidelines
Eaton · oem · confidence medium · accessed 2026-05-05
Registered as an Eaton support and service-information context source. Not used alone for fault-code meaning.
View source ↗Navistar Engine Diagnostic Trouble Code Body Builder References
Navistar / International Truck Body Builder · oem · confidence medium · accessed 2026-05-05
Registered as a future discovery path for Navistar engine DTC references. Individual pages require specific source extraction before indexing.
View source ↗NHTSA Manufacturer Communications for Volvo Trucks and Mack Trucks
National Highway Traffic Safety Administration · government · confidence medium · accessed 2026-05-05
Registered as a future discovery path. Do not publish Volvo or Mack code mappings without a specific public communication or OEM document.
View source ↗NHTSA Manufacturer Communications for PACCAR Vehicles
National Highway Traffic Safety Administration · government · confidence medium · accessed 2026-05-05
Registered as a future PACCAR discovery path. Individual fault-code claims need a specific document source.
View source ↗NHTSA Manufacturer Communications for Allison Transmission
National Highway Traffic Safety Administration · government · confidence medium · accessed 2026-05-05
Registered as a future Allison discovery path. Not used alone for indexable transmission DTC meanings.
View source ↗Cummins Service Support Public Resources
Cummins Inc. · oem · confidence medium · accessed 2026-05-05
Registered as an official support context source. It is not used to publish specific Cummins fault-code meanings without a more specific public source.
View source ↗TOOLBOX PLUS Diagnostic Software
ZF Commercial Vehicle Solutions · oem · confidence medium · accessed 2026-05-05
Used only for WABCO/ZF ABS diagnostic-tool context. No diagnostic tables are copied.
View source ↗Roadranger Support
Eaton · oem · confidence medium · accessed 2026-05-05
Used only for Eaton support and service-information context. No service manual text is copied.
View source ↗Allison Transmission Service and Support
Allison Transmission · oem · confidence medium · accessed 2026-05-05
Used only for Allison official support context. No diagnostic text is copied.
View source ↗Detroit Diesel Service and Support
Detroit Diesel Corporation / Daimler Truck North America · oem · confidence medium · accessed 2026-06-09
Registered as an official Detroit OEM support context source for DD13/DD15/DD16 engine fault codes. Used only to identify Detroit/DTNA service information as the authoritative diagnostic verification path. No service manual text is copied.
View source ↗PACCAR Engine Technical Services
PACCAR Inc. · oem · confidence medium · accessed 2026-06-10
Registered as an official PACCAR OEM support context source for MX-13 and MX-11 engine fault codes. Used only to identify PACCAR/Kenworth/Peterbilt service information as the authoritative diagnostic verification path. No service manual text is copied.
View source ↗Volvo Trucks / Mack Trucks Technical Support
Volvo Trucks North America / Mack Trucks Inc. · oem · confidence medium · accessed 2026-06-10
Registered as an official Volvo/Mack OEM support context source for D13 and MP8 engine fault codes. Used only to identify Volvo Trucks NA and Mack Trucks service information as the authoritative diagnostic verification path. No service manual text is copied.
View source ↗Freightliner Trucks Service and Support
Daimler Truck North America LLC · oem · confidence medium · accessed 2026-06-10
Registered as an official Freightliner/DTNA OEM support context source. Freightliner Cascadia and other DTNA vehicles use Detroit Diesel DD13/DD15/DD16 and Cummins powertrains; fault codes reflect those OEM diagnostic systems. Used only to identify the authoritative service verification path. No service manual text is copied.
View source ↗International Trucks Service Support Public Resources
International Trucks / Navistar International · oem · confidence medium · accessed 2026-06-11
Registered as an official International Trucks / Navistar OEM support context source for A26, A13, and MV Series engine fault-code educational content. International ServiceMaxx is the authoritative diagnostic tool. No service manual text is copied.
View source ↗Volvo Trucks Tech Info Public Resources
Volvo Trucks North America · oem · confidence medium · accessed 2026-06-11
Registered as an official Volvo Trucks OEM support context source for Volvo D13 and D11 engine fault-code educational content. PTT (Premium Tech Tool) is the authoritative diagnostic tool for Volvo engines. No service manual text is copied.
View source ↗Mack Trucks Service Support Public Resources
Mack Trucks Inc. · oem · confidence medium · accessed 2026-06-11
Registered as an official Mack Trucks OEM support context source for Mack MP8 and MP7 engine fault-code educational content. Mack PTT is the authoritative diagnostic tool. No service manual text is copied.
View source ↗Allison On-Highway Automatic Transmissions Service Support
Allison Transmission Inc. · oem · confidence medium · accessed 2026-06-11
Registered as an official Allison Transmission OEM support context source for 3000 and 4000 series automatic transmission fault-code educational content. Allison DOC (Diagnostic Optimized Communication) is the authoritative diagnostic tool. No service manual text is copied.
View source ↗Ford Trucks Service Support Public Resources
Ford Motor Company · oem · confidence medium · accessed 2026-06-11
Registered as an official Ford OEM support context source for 6.7 Power Stroke and 7.3 Power Stroke engine fault-code educational content. Ford IDS (Integrated Diagnostic System) and FDRS are the authoritative diagnostic tools. No service manual text is copied.
View source ↗Isuzu Commercial Trucks Service Support
Isuzu Commercial Truck of America · oem · confidence medium · accessed 2026-06-11
Registered as an official Isuzu Commercial Trucks OEM support context source for NPR/NQR/NRR trucks with 4HK1 and 6HK1 diesel engines. Isuzu IDSS (Isuzu Diagnostic Service System) is the authoritative diagnostic tool. No service manual text is copied.
View source ↗GM Trucks Service Support — Duramax Diesel Resources
General Motors LLC · oem · confidence medium · accessed 2026-06-11
Registered as an official GM OEM support context source for Chevrolet Silverado HD and GMC Sierra HD trucks with Duramax diesel engines (L5P and LML generations). ACDelco TDS and GM TIS2Web are the authoritative diagnostic tools. No service manual text is copied.
View source ↗Cummins INSITE Service Tool — Public Reference Documentation
Cummins Inc. · oem · confidence medium · accessed 2026-06-11
Registered as an official Cummins OEM diagnostic tool reference for ISX15, X15, ISB 6.7, and X12 engine families. Cummins INSITE is the authoritative dealer and fleet diagnostic tool for fault code reading, live data, and actuation tests. No proprietary software or manual text is copied.
View source ↗Detroit Diesel Service and Diagnostic Resources — Public Reference
Detroit Diesel (Daimler Truck North America) · oem · confidence medium · accessed 2026-06-11
Registered as an official Detroit Diesel / DTNA OEM support context source for DD13 and DD15 engine families. DiagnosticLink (replacing older DDDL) is the authoritative diagnostic tool for Detroit engines. No service manual text is copied.
View source ↗PACCAR / Kenworth / Peterbilt Service Support — MX Engine Resources
PACCAR Inc. · oem · confidence medium · accessed 2026-06-11
Registered as an official PACCAR OEM support context source for MX-13 and MX-11 engines in Kenworth and Peterbilt trucks. PACCAR ESA (Electronic Service Analyst) is the authoritative diagnostic tool. No service manual text is copied.
View source ↗Eaton Roadranger Technical Resources — UltraShift and Advantage AMT Service Documentation
Eaton Corporation (Roadranger) · oem · confidence medium · accessed 2026-06-11
Registered as an official Eaton Roadranger OEM support context source for Fuller UltraShift, Advantage AMT, and manual transmission products. Eaton ServiceRanger is the authoritative diagnostic tool for these transmissions. No service manual text is copied.
View source ↗Unverified sample record placeholder
Truck Fault Codes editorial placeholder · unverified · confidence low · accessed 2026-05-05
Used only for non-indexable sample records while the data model is being tested.
FAQ
What types of sources does this site use?
Primary sources are U.S. federal regulations (FMCSA, eCFR), SAE J1939 standards, EPA emissions guidance, and OEM-published technical documentation from manufacturers including Cummins, Detroit Diesel, Bendix, and WABCO. Secondary and industry sources are used only where primary sources are unavailable and are flagged accordingly.
Can unverified sources support indexable pages?
No. Pages must be tied to at least one source rated high or medium confidence. Unverified sources may be used only for lead discovery — they cannot be cited to support diagnostic claims on indexed pages.
Are source texts copied into pages?
No. Every page uses original educational summaries written against the listed sources. Source text is not reproduced. The goal is explanation and terminology, not reproduction of official documents.
How often are sources reviewed?
Access dates are recorded for each source. Regulations and guidance documents can be updated, and pages tied to those sources are flagged for re-review when changes are identified. The last-reviewed date on each page reflects the most recent check. See the methodology page for the full review workflow.