I had a similar issue with my 2007 RX350 with 59,900 miles on it. THe Check Engine light and the VSC light. The Lexus dealer said it had code P2195 and I needed to replace an A/F sensor. Since I was above 50,000 miles, he said it was not covered by warranty and would cost around $500 to replace. He said that as a goodwill gesture they'd split the cost with me. When I picked it up I was charged $250 for labor, plus about $37 for Hazd./Shop charges. They also had me sign a 2nd invoice so they could recoup about $220 from Lexus.
As I look back at it, I'm wondering if the charges were appropriate.
I literally just had this happen to me and why I became a mbr of the site. My 2007 RX350 has a little under 30,000 miles on it and all of sudden the VSC and check engine light came on. I scheduled service and then did a search online.
I kid you not, I opened the gas cap and then put it back on until I heard a couple clicks,,,,the lights went right off. So check this first and thank for all the good info!