Replacing O2 Sensors

[normrd]

How difficult is it to replace the O2 sensors for a RX300. Mechanic said check engine code was due to a bad O2 sensor and that we should replace both.

Where are these located? Best place to buy them?

[normrd]

Acutally, I was told it is the front two Air/Fuel Ratio sensors that need to be replaced. I have not been able to find these anywere except the dealership for $300+ each. Any one know of another source for them?

[AWJ]

Call your dealership and ask them how many 02 sensors your vehicle has. If it is the 2jz motor then you have 2 - not sure on the newer one though you may have three. They are located in your exhaust system. They do monitor the air to fuel ratio of the cumbustible mix in your motor. It is recommended to use a special wrench on these things. I've never done the job though. I saw the wrench on e-bay for sale - toyota parts search. When you talk to the delearship, ask them the part number for the 02 sensors. Then call another dealership and ask them the same question to make sure they are telling you the correct info. Once you have the correct part number, call NAPA or another automobile parts store and ask them in they carry toyota o2 sensors and give them your part number. If they don't have the exact part, they will probably have a cross-reference from a company like Bosh or Delco or something. As far as actually doing the job, that is going to be easier or harder than getting the parts depending on your abilities and the tools. Take your time and you should be fine. I'd recommend getting your hands on the factory service manual for your vehicle. The delearship is the only place to get those usually. They cost up to 200+$ for 2 to 3 volumes but they cover all jobs and are worth their weight in gold. That is the book they use in their service departments to fix our cars.