Likely causes, most common first
Misfire
P0300-series codes. Flashing light means stop driving.
Catalyst efficiency below threshold
P0420/P0430 — fix the cause before the cat.
Loose or failed fuel cap / EVAP leak
Very common and often free to fix.
Oxygen or MAF sensor fault
Check for vacuum leaks before replacing sensors.
Checks to run first
- 1.Scan the code and write it down
- 2.Flashing light = stop driving
- 3.Look up the code before buying parts
Frequently asked questions
- what does the check engine light mean?
- The light only tells you a monitor failed. Read the code first — a $25 scanner turns a guess into a diagnosis.
- Is it safe to drive with this?
- Short local trips are usually fine, but the fault will get worse and often damages other parts if you leave it.
- How much does it cost to fix?
- The most likely repair is spark plug replacement, which runs $80–$675 in the US including labour, or $25–$180 in parts if you fit it yourself.
Engine & drivetrain parts
Filters, belts, pumps, plugs, clutches and gaskets
Find parts that fit
Year, make, model, trim — then only parts that fit your car.