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Toyota Repair/Location of Bank1 Sen1 O2 Sensor


My 2003 Toyota Camry XLE, 2.4 engine (2AZ-FE) is showing a code of P0031. I'm trying to find the exact location of that O2 sensor so I can fix it myself. I also see that Auto Zone has 2 different parts numbers for this sensor: 1 with CA emissions & 1 without. How do I know which to buy? I'll need some detailed instructions on how to replace the sensor. Will I need a special tool?

Hello, this engine has four sensors, two at the top of the exhaust manifold before the catalytic converter and two at the bottom, one cat converter for each bank and two sensors for each, the #1 sensors are at the top, the sensor #1 is at the right side if the manifold standing in front. California emission certified engines have air/fuel ratio sensors instead of O2 sensors, to find out which type you have check the label on the inside of the hood, if it says certified for federal and California emission standards it is considered CA certified, if it only says certified for federal emission standards it has O2 sensors, you will need an O2 sensor socket to remove it, the autoparts stores should have this also.
If your exhaust configuration looks different than what I described let me know or if possible attach a photo, Toyota made some changes later and went back to the single converter configuration which has one sensor before the cat, in either case the #1 sensors are always in front of the cat converter.  

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Ted Ritter


I have more than 28 years experience as toyota technician, I will be able to answer most questions related to the Toyota product line up to the present year models,I am located in the US but welcome questions from other regions of the world. When asking a question please provide specific information: year,model, engine,transmission information. Provide as much information as possible including a brief repair history if possible. I have been a volunteer here for more ten years an have answered over 16,000 questions helping Toyota owners with their problems and save thousands of dollars without any compensation, some of my answers are published on many other websites including google and various automotive forums. DONATIONS ARE VERY MUCH APPRECIATED, IF YOU HAVE RECIEVED HELPFUL INFORMATION PLEASE MAKE A DONATION. AS OF TODAY (JULY 22, 2014) ALL REQUESTED GRAPHICS, ILLUSTRATIONS, DIAGRAMS, PHOTOS, WILL REQUIRE THE MINUMUM DONATION UP FRONT.


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