My El Dorado has a bad sensor on the transmission. The dealer told me that it would cost around $5K to repair it-a very reasonable part but expensive labor to drop the transmission etc. I can't seem to access the on board computer to reset the Service Engine Soon light-I've been pushing the OFF/Passenger Temp buttons at the same time but the only message that comes up is "Apply brake to shift from park"....Can someone help me? I don't think I'm doing something right......