Use a code as a starting point
A diagnostic trouble code identifies a detected system or condition; it does not by itself prove which part has failed. Review symptoms, related checks and vehicle-specific information first.
SCNAUTO OBD-II Fault Code Finder
OBD2 Fault Code Finder: Meanings & Diagnostic Checks
Search OBD-II diagnostic trouble codes by code or symptom, then review meanings, likely causes, diagnostic checks and repair guidance.
Manufacturer-specific codes
Some DTC meanings vary by manufacturer. Confirm the vehicle make, model and year before acting on a manufacturer-specific definition.
Check owner manualPopular OBD-II code guides
P0300 misfire · P0171 lean condition · P0420 catalyst efficiency