germangs

I ended up ordering upstream sensors yestarday from Amazon. I will keep you posted on the progress. I hope replacing upstream sensors will get the codes clear. We'll see. Thank you everyone.

BlackCat81

Upstream sensors won't fix a catalyst code, just like the gas cap didn't. Upstream sensors are air fuel sensors, not oxygen sensors. You can try running a spacer in the rear sensors to slow their response, which may buy some time and keep the light off.

How much money do you have wrapped up in throwing sensors in hoping to clear a code? You're probably half way to replacing a cat anyways.

germangs

I don't think I will get the cat converters replaced. I'd rather trade it in for another good car instead. Anyway I did the job replacing downstream sensors, not much labor involved to do that. The upstream sensors were more complicated to replace. It required some tools and parts l to get this done.
I replaced the upstream passenger side sensor without problem.
The driver side upstream sensor is a pain. I could not remove it. It stuck while removing it. I am afraid I can break it if I continue to stress it.
I still have warning lights on and after scanning I was able t pull two codes again. P0430 for bank 2 and P0051 Oxygen sensor (A/F) heater Control circuit low (B2S1).
I just wanted to confirm it is because of the stuck sensor.
If this is so I'd rather to bring the car to local shop so they drop the pipe and the cat down to get it done the right way.

Ali SC3

iTrader: (10)

heat it up and itll back up like butter. let the car idle for like 15-20 minutes and try again.
I know they say work on a cool exhaust not to burn yourself, but if you wear arm protection and work on a hot exhaust the o2 sensor comes out with no fuss. on a cold exhaust I have stripped out more than a few they don't like to come out really.

germangs

So, what side the bank 2 is on, driver or passenger?

chiph9

Bank 2 is the set downstream from the catalysts. There are separate left & right parts.

Bank 1 is ahead of the catalysts, and they both use the same part.

This diagram shows it (click on the "Fullsize" link).

http://www.lexussouthatlantaparts.co...roduct=5794277

Chip H.

JPMcL

Hello germangs, another MA resident with the same problem. Did you resolve the issue and if so, what finally nailed it? Thanks in advance. JP

ssgi4in12

Pls see the update https://www.clublexus.com/forums/rx-1st-gen-1999-2003/846095-help-me-find-the-culprit-for-p0420.html#post9758078