It means that something occurred or failed that is emission related witch if not fixed it may cause unwanted emissions into the air and it cause make you get worse gas mileage. The computer has stored a code to identify the problem, you can go to Auto Zone or Advance Auto Parts or similar parts store where they will hook up a code reader to your car & tell what code/device failed. Most auto parts stores do this for free. Then you can purchase the part & change it yourself. If you are not mechanically inclined then any auto shop will be able to take care of it for you, I would suggest getting the code read for free & buying the part yourself, then taking it to a shop for install. It would save you some money.
If you change the part yourself, disconnect the battery when you start and keep it disconnected for a minimum of 20 minutes, this will refresh the computer and allow the code to reset.
Check and fix the engine.
it looks like a little orange engine in lower left on dash
Follow the troubleshooting tree that is associated with that code.
With an OBD2 scan tool. The problem must be repaired or the light will just come back on.
If the Check Engine light is lit or has lit, that means the computer has detected a fault in either the performance or emmissions system of your vehicle. Have the OBDII terminal scanned for the trouble codes.
If the check engine light is blinking that means that an engine cylinder misfire has been detected . You can drive it in for repair , just avoid any rapid acceleration or deceleration because you can damage the catalytic converter
On a 2000 Mercury Cougar : The warning light that looks like a can with an X through it , located between the engine coolant temperature gauge and the tachometer ( at the bottom of the gauge cluster ) is your ( LOW engine cooling system warning light )
On a 1997 Mercury Mountaineer : The " CHECK ENGINE " warning light is just to the left of the battery voltage gauge
If your check engine light is flashing , an engine cylinder misfire has been detected
my check engine light stays on and the o/d light blinks....what could this mean?
Either your gas tank is at or near empty , your oil pressure is too low , or your engine coolant temperature is too high
If the check engine light is blinking that means that an engine cylinder misfire has been detected