why is the 'check engine' light staying on in my Toyota Corolla?

The check engine light comes on for a number of emissions related failures. From a leaking gas cap, to a poorly running engine, to a faulty catalytic. There are many many codes that can set in the computer to turn te light on. Take it into a mechanic and have it scanned to find out what code(s) are stores and then have the specific repairs made to correct those problems.

Good luck!

If the light is staying on take it to a service center. It is hard to say what is causing it without taking a look. I can say it is not the gas cap... it almost never is.

U need to check the engine

actually at every time when u insert d key d engine check light blinks

if it blinks rapidly then check d break oil,wipre water,engine oil,coolent oil tatz it

hope itz help

Take it to a mechanic. There may be a leak or some more significant problem.