US vehicle warning and code research
Car warning lights and
OBD-II codes.
Choose the safe next step.
A dashboard light is a clue, not a parts shopping list. Start with safety, then use the exact vehicle and source.
Find the answer you need
Select a documented vehicle
Only years backed by a source in this research set appear. The selection narrows the manual; it does not certify a code or part fit.
Use your vehicle, not just a code
Our researched records cover selected US makes and documented configurations. A model name alone never proves that a code or part applies.
Practical next steps
Common questions
Does P0420 mean I need a catalytic converter?
No. The code reports a catalyst-efficiency condition. A shop should check other codes, exhaust leaks and system data before choosing a part.
Can a basic OBD reader scan ABS or airbag codes?
Only if its manufacturer confirms exact vehicle and module coverage. A generic emissions reader alone does not guarantee it.
Will clearing a code pass an emissions inspection?
Clearing can reset readiness monitors. Repair the cause and check your state’s current inspection rules.