check engin light on on 1997 Honda Civic

check engin light came on, i called my mechanic, they said to check fuels and see if that helps. since the car was due in 2 weeks for an oil change i had it done and asked for the other oils to be topped up and an engine flush done. This was done, engine light went off. a few days later its back on. its impossible to be out of fluid already and no evidence on my drive way of a leak. What's the problem? Thanks

Asked by for the 1997 Honda Civic
Have your mechanic scan your car for codes and he will know exactly what is turning the light on