What does the Check engine light mean?

The engine computer has logged a fault in the engine, emissions or transmission systems.

How much does it cost to fix the Check engine light?

Typically $0 to $1,200 in the US, depending on the cause. From tightening a fuel cap to replacing a catalytic converter; most causes fall under $400.

Check engine light: meaning, urgency, cost

Urgency:Service soon

Is it safe to keep driving?

Usually yes if the light is steady and the car drives normally. If it is FLASHING, pull over — a flashing check engine light means an active misfire that can destroy the catalytic converter within minutes.

Likely causes

Loose or worn fuel cap (the single most common cause)
Oxygen sensor failure
Ignition coil or spark plug misfire
Catalytic converter efficiency below threshold
Evaporative emissions (EVAP) leak
Mass airflow sensor fault

Typical repair cost (US)

$0 – $1,200

From tightening a fuel cap to replacing a catalytic converter; most causes fall under $400.

A typical range, not a quote. Actual cost depends on the car, the shop and the fault.

What to do now

Check that the fuel cap is tight and drive a few trips — the light may clear itself.
Have the stored trouble code read. Many US auto-parts stores read OBD-II codes free.
If the light flashes, stop driving and have the car towed or inspected the same day.

Read the full guide →Check your VIN for open recalls →All warning lights