I've done both - dealership and corporate. Thy both are telling me the same thing. Part is no longer available. I'm out of luck.
The General Manager of Hendrick Lexus of Charleston, David Yarborough didn't have any remedy and was not willing to pay for a vehicle with the part (I suggested they find same model with high mileage that doesn't cost much, buy it, and use the part). By the way, it's not just the sensor, it's the computer that goes with it. He offered for us to trade it in - for the value of it with defective part (which isn't much!). No thank you! They would consider fixing with a used part (that they are not willing to pay for) only after evaluating where the part is coming from and if we sign a release from liability. Needless to say, none of this was acceptable.
I told him that I was not going to walk away quietly - I was going to contact his corporate office and that I would also post on multiple forums, send letters to editor of newspapers, and make as much noise as I can. I've never Tweeted before but am told that companies monitor Twitter so I will pursue that as well, if necessary.
I contacted Hendrick's corporate office in Charlotte and got a very nice call back. The person is going to get back to me tomorrow, but did ask if we were open to getting a comparable car with low mileage if Lexus would pay for it. That's the first positive response I've heard to date!
I also filed a claim with the Nat'l Highway Traffic Safety Admin. and they will determine if it warrants an investigation. They said I can also file a claim with the Federal Trade Commission.