A check engine light code showed Bank one sensor one on my 3.0 liter 6 cylinder engine. It is against the fire wall so I had it done, but they could not get rid of the check engine light. I disconnected both battery cables as is a common practice, but also did the following...I touched both cables together for about thirty seconds and then reattached them to the battery. I turned the key to ON position, turned on the AC, and then started the car. The car ran smoothly right away AND the light stayed off with an added bonus...the pulsing in the acceleration when climbing a hill or even stepping on the gas from stop that I have reported earlier was gone as well. Apparently these sensors cause problems well before any code shows up (that pulsing had been going on for over a year, but without a code I heard everything from "I don't feel anything" to "it's a transmission problem")). That's just something to keep in mind when your car just doesn't seem to be "acting" right but there is no check engine light on when you might expect one.