WhyLamp Names the Problem Behind Your Check-Engine Light

Field notes

The lookup accepts the five-character scanner code and can also use a vehicle’s make and model to distinguish common definitions from brand-specific ones. Results are organized around meaning, urgency, at-home checks, likely shop attention, and explicit limits on what the site can know. The visible example is P0420, and the page points readers to SAE J2012 and U.S. EPA material rather than presenting an uncited diagnosis. Planned Garage history and Reader kit features are not available for purchase.