On a lexus rx330 bank one sensor 1 is upstream or downstream

SOURCE: oxygen sensor confusion

1/1 is upstream sensor on the number 1 cylinder side, 1/2 is the downstream of the number 1 cylinder side, 2/1 is the upstream of the number 2 cylinder side, 2/2 is the downstream of the number 2 cylinder side. Hope this helps.

Testimonial: "sorry, I hit the submit testimonial button before thanking both of you who so promptly answered. "

SOURCE: Getting PO141 trouble code when scanning! Car '03 accord, 2.4 ltr

i spoke to a honda tech , and he confirmed code p0141 on the 4cylinder model is the second sensor.

SOURCE: 420 code catalyst system efficiency below

You could have an enefficient converter. Question is what caused it to go bad? I have attended seminars on code 420, Possible causes are lack of spark or clogged fuel injectors. there have been times where the spark plug wire lays on the engine and over time it wears a weak spot in the side of the wire, its not enough to throw a miss fire code but it keeps the full amount of spark from getting to the plug and not burning the all the fuel in the cyl. A leaky injector would also cause to much fuel to be deliverd into the cyl and not get burned.

Hope this helps.

SOURCE: 04 sebring conv, 2.7 l V6, Trouble code for Bank 1

The O2 sensor is the left side (sitting in vehicle) downstream sensor. Also refered to as 1 / 2 sensor.

SOURCE: Honda ridgeline oxygen sensor bank 2 sensor 1;is

Here is how you guys can tell, which bank it is...Rule of thumb..Bank 1 is where the first piston firing order is.....Which in the Honda Ridgeline is in the rear...If you look at the motor its side ways ok...The best way to judge the first piston is to look at the spart plug cover....the one that is the closest to you is the first piston....Remember your looking at the engine as if it were straight, however honda ridgeline is side ways...So the front of the piston is on the passenger side...Ok...I hope this helps...