TruckDiag turns hard-won Class 8 repair knowledge — fault codes, known failure points, field procedures and live-data targets — into one fast, reliable reference for diagnosing 18-wheelers and heavy trucks. Spend less time hunting through PDFs and forums, and more time fixing the truck.
Enter a code or symptom and get the likely meaning, derate risk and probable causes across makes.
Step-by-step field procedures that call out the blockers and safety warnings that actually matter.
Know the correct live-data values for DEF, NOx, SCR and regen before you condemn a part.
Get a scanner recommendation matched to the makes you service and your budget.
Answers in seconds instead of hours digging through service literature.
Decisions backed by documented failure points and OEM-aligned specs.
Use it in the browser, or connect it to the tools and assistants your team already runs.
Curated and continuously updated, with instant cached lookups.
Advisory reference only — verify against OEM service literature and the specific VIN/build before performing repairs.