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The covertor is most likely bad and the Check engine light will come back on. It is just a matter of time. But the light may also have come on just from electrical interference in the car and popped teh light on and there may be no problem. I have noticed with the Kia's that it may take a while for the ligtht to come back on. If you have to put the car through emmisions soon it may not pass. My suggestion is this, If you have no driveability problems with the car, Keep driving it. You really can't hurt the car more than it already is. If the light never comes back on. Then you got lucky.