P1155 Air Fuel Metering or oxygen sensor?

Hi LxsES300 and welcome to 2carpros

The B2S1 is located on the left exhaust manifold see item location no.13 below and this guide will walk you through the steps with instructions in the diagrams below for your car. Here are all of the oxygen sensor locations. Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

I was told after a recent diagnostic of a check engine light that the B1S1 O2 sensor (before catalytic converter) and MAF sensor had failed. I asked the service man if a failure of the O2 could make it appear that the MAF had failed which would make sense to me if that particular O2 sensor were a feedback to the system containing the MAF. He said no. What is your opinion?

I have seen Chilton's and Mitchell's repair manuals referenced in responses. Are either of these a good manual for a "beginner" like myself?

Ok first I would replace the O2 sensor and then get some mass air flow cleaner and clean the mass air flow and then go to a parts store that offers a free scann and have them clear the codes if it comes back then go from there.