Check Ingine, Vsc, Vsc Lights On

[justnew]

Good Afternoon, I hope you can help - a few days ago my check engine, VSC and VSC off lights came on - after going to the Lexus dealership (and $100 later!!) the sheet says they found code P0158 bank 2 sensor 2 02 sensor high voltage (found internal fault). I think we are going to try and fix ourselves but don't know which one to purchase (they had a code of 89465-24210, which we think is Densa??). My question though is where do we find that 02 sensor on my car to replace? Does anyone have a diagram?