im assuming that you were using a map sensor check valve before, since you've had the turbo on for a year, right??? if not, it's not very healthy for the car, cause the ecu doesn't know what to make of the +pressure. other than that, i've thrown a few codes since, but i think it's because a vacuum line let out some pressure or something, cause nothing really bad happens cept the car stalls....i just start it back up again and it's fine. also, to reset the light, just remove the negative battery cable and your ecu is reset and the light will go off. good luck!