right next to ur ecu there should be a clip there, it might be hidden behind the glove compartment, just search a bit. its green. there is 1 clip w/ 2 open pins. stick a paper clip or some wirring and connect them. turn ur key on / engine still off, check engine light should blink a series of times, called codes. record, and look in manual or h-t for code description. that should tell you y ur check engine light is on.