I just took my car for a smog check and it failed coz the engine light was on and it was giving the code P0770. I was told it may have something to do with the transmission. I don't see anything wrong with my transmission, but I took it to the mechanic anyway to be sure and they confirmed nothing is wrong with my transmission. So why is my engine light still on then? Does anyone has any idea what else it could be? The light is off after I took it to the mechanic, but it will come back on as soon as I drive off. Plz help.