There are 3 Oxygen sensors on Lexus RX300.
I have replaced the 2 forwards ones so far.
The third one is Post- Catalytic converter and requires drivers seat removal to get at the electrical connector.
It is also difficult to remove the O 2 sensor from the exhaust system because it is mounted into an exhaust hanger.
http://www.autoshop101.com/forms/h37.pdf
Cylinders 1,3, and 5, the sensor after the catalytic converter. Find the exhaust pipe coming from the front of the vehicle and follow it until you see the O2 sensor after the catalytic converter.
A/F Sensor for Bank 2 Sensor 1. It is the O2 sensor on the front manifold.
It is a real pain. My suggestion is to take it to a shop.
It just cost me $220.00
$300 with labor
Stop by your local AutoZone. They will hook it up to a handheld tester and print out which oxygen sensor is failing.
The oxygen sensor is "done". It should be replaced.
Depends on what the problem is or what code was set.
4 wires, the black ones are the O2 heater (on the sensor side), the white and green are the O2 sensor itself
There are three O2 sensors. Bank 1 Bank 2 and a down stream one. Make sure your changing the right one. Get an O2 sensor socket. After your rx is cooled down, spray penetrating oil on the threads of the bad sensor, let it soak, go inside and have lunch. When your done eating unclip the harness of the bad sensor. Use your O2 socket and turn out the old sensor. Apply anti-sieze to the threads of the new sensor and install it. Plug it back in.
the exhaust, where every o2 sensor is