It is sensor 1bank 1. Bank 1 is closer to passengers. (Bank 2 is closer to front of vehicle). There are 3 total “oxygen” sensors. Two are pre cat. Literally speaking, the 2 pre cat ones are called”A/F” or air/ fuel sensors but it’s not uncommon to hear them called oxygen sensors and everyone knows what that means. The third one is post cat.
The Bank 1 sensor itself is accessible from under the car. The wire connector connects just underneath the Intake manifold (on the right from above). It can be reached from above or below.
P0171 O2 Sensor 1 or Sensor 2?
in 99 - 03 Lexus RX300
Posted
It is sensor 1bank 1. Bank 1 is closer to passengers. (Bank 2 is closer to front of vehicle). There are 3 total “oxygen” sensors. Two are pre cat. Literally speaking, the 2 pre cat ones are called”A/F” or air/ fuel sensors but it’s not uncommon to hear them called oxygen sensors and everyone knows what that means. The third one is post cat.
The Bank 1 sensor itself is accessible from under the car. The wire connector connects just underneath the Intake manifold (on the right from above). It can be reached from above or below.