jus disconnect battery overnight, sometimes it works, sometimes it doesnt, mine was off overnight 2 days ago and it didnt take the MIL off. Same with SRS control units they have resistors in that hold alot of power once the source is taken away. best bet is to unplug the ecu its self and try that overnight or jus get it code read. if theres a current fault, after a complete drive cycle the MIL will come back on and your back to square one. if its a stored fault then it will stay off.