Could I get a part number or link to what I need? Can't seem to find if it's an 02 sensor or air fuel sensor. I have the code p0031 right now. Any tips on how to get at it? I hear it's tricky. Thanks

The P0031 fault code does not mean that you just automatically replace the O2 sensor. The code is actually for a fault in the sensor heater (integral part of the sensor) or it could be caused by a problem elsewhere in the heater circuit. If you Google "P0031 Lexus code" you'll get some basic info. Please read the troubleshooting list. The Bank 1, sensor 1 is the O2 sensor for the aft cylinder bank and the one closest to the engine (upsteam of, or in the inlet of the cat). Are you sure that you are not covered by your Emissions Warranty?

I got the same thing. Bank 1 Sensor 1 is an Air Fuel Sensor, not an O2 sensor. Be careful when ordering the part.....and don"t ask how I know!!!

You mean, MAF sensor?

No, Air/fuel ratio sensors. They look identical to O2 sensors but Lexus calls them Air/Fuel Ratio Sensors.

They are the same thing and if you don't want to believe it then order the part from Lexus. The only difference between O2 sensors is some have heaters and some don't. The function of an O2 sensor is to measure the air/fuel ration and provide that info to the ECU . http://en.wikipedia.org/wiki/Oxygen_sensor

They may function the same way, but they are something different. Check the Denso website. They list 2 O2 sensors and 2 air/fuel ratio sensors. They are not all interchangeable.

One type has a heater circuit in it that usually burns up in time. The other does not. All of them perform the same function and are only different depending on the wire pigtail. The heater is there to speed up the transition from open loop (rich) to close loop .

The left hand is Bank 2 (radiator side on front wheel drive vehicles). Basically when they talk about sides you should think as if you are standing at the back of the vehicle and the engine is in a front engine rear wheel drive configuration. That leaves RH (firewall side on front wheel drive vehicles) as Bank 1.



Keep in mind that Bank 1 is determined by #1 piston side and if a motor had #1 piston on the radiator side (front wheel drive) then "left hand" would become bank 1 in that situation.

old thread but best info

https://www.clublexus.com/forums/es-...nsor-info.html