Hello All,

My mom is having issue with a sensor on her 2003 IS 300. I will add pictures but it is located at the back-driver side if you were standing in front of the car looking at the engine. I believe its a O2 sensor but I am not sure. Can anyone verify?

Thanks in advance.

 

That's not an O2 sensor. That's a little filter thingy that's part of the EVAP system.

Our cars have 4 O2 sensors:
2 primaries, pretty visible at the merger of cylinders 1-3 and 4-6. Both before the 2 cats.
2 secondaries, one visible in the engine bay behind one of the cats. Look at the back of the firewall near the battery - then look down. The other O2 is under the front passenger-seat floor