2003 Lexus ES300 Bank 1 Sensor 1 Air/Fuel Ratio Sensor Location and Replacement Difficulty

wonderdog wrote: Our local Lexus dealer has diagnosed a faulty Bank 1 Sensor 1 Air/Fuel ratio sensor on our 2000 Lexus ES300 and is charging a high price for replacement. Can anyone confirm the exact location of this sensor on the 2000 Lexus ES300 and how accessible it is during repair? We're concerned about both cost and technical difficulty, especially given that we have limited mechanical experience. Any insights would be greatly appreciated. It's located in the rear exhaust manifold. Access can be challenging—some users report significant difficulty, particularly with tight spaces and access points as shown in this reference image.

Thank you for your response, I appreciate it very much! It looks difficult to reach, especially for someone my age with back problems. This could make the repair even more daunting without proper tools or experience.

No fun—just be sure to get an OEM part. A 'fuel/air ratio sensor' is not the same as an oxygen sensor; confusion between these components can lead to incorrect repairs and poor performance.