MrHimbert

So I have a 2003 GS300 with 127,XXX miles....car was acting very sluggish and eating gas terribly so i decided to clean the MAF sensor and throttle body which was very dirty. In my haste to get it done, i did not unplug the negative terminal. So coincidentally, my car threw CEL as well as the traction control and what not being deactivated (still makes no sense why this happens). A

Anyway so I unplugged the negative side a couple times, tried resetting the codes a couple times, and within about 5 mins of driving. They come back on. From the search i did, the P0154 is the bank 2 sensor 1 (one of the sensors on the front CATs im assuming?).

As far as the p0430 goes, ive read that that could be the sensor on the number 3 CAT or possibly the CAT itself.
Also, I am running NO RESONATORS, with a couple magnaflow 40 series mufflers. This was done well over 3 years ago though. Could it possibly be that overtime, the change in back pressure, could have killed my sensor and the CAT?

I have SMOG and registration coming up and need to fix this ASAP. But i dont want to wildly replace parts.
When I was cleaning everything, the only things i unplugged was the MAF sensor plug, and one plug on the throttle body setup, which i cleaned with ISO alcohol. I didint notice any pinched wires or anything, but i supposed i can check agian.

What is the best solution, or next step in troubleshooting? How can i test the 02 sensors at home? My exhaust does smell pretty strong from time to time. a little stinky, but mostly smells like excessive amounts of gas. Im thinking that that smell is from running too rich, which sounds like a sensor. I dont know....a little stumped....any information will help. thank you very much.

MrHimbert

Or maybe one of the front sensors is indeed bad, which is a temp sensor, creating a bad mixture of air to fuel? causing the excessive gas smell?

MrHimbert

I am also having trouble identifying which is which. seems everyone on the internet has a different answer of which sensor is bank 2 sensor 1.

MrHimbert

untz, ha, untz ha, untz, untz, ha, ha, untz-ha, untz-ha.

Mcon

iTrader: (1)

Bank 1 is the first manifold that go on the piston ( 1, 2, 3 ).
Bank 2 is the second manifold that go on the piston ( 4, 5, 6 ) .

Sensor 1 is the first sensor close to the manifold, the engine or upper position..
Sensor 2 is the sensor far away from the manifold the engine or lower position.

So, every manifold have 2 sensor

In your case, Bank 2 is the second manifold, first sensor in that manifold. I hope this help U. Go to eBay and if you have the money. Buy all 4 sensor in one combo like I do and all you headache go away. Believe me for my baby work much better after I do that. Is arrown $365.00 for all 4 and 1 year warranty.

burny

^ what that genius said

GsLex02

3rd CAT has no sensors so your car will never know if it is bad.

GeorgeGS4

Top reasons why a 420 or 430 code will trip:

converter failure
oxygen sensor failure
exhaust leak

I myself had same code and found a small hole after the converter, repaired and cleared MIL. You may have a small exhaust leak (check with soapy water while running) If there's no leaks, you'll likely need your Bank 2 sensor 1 oxygen sensor replaced (as you also have a p0154)

From my experience if you want a permanent fix, use a TOYOTA/LEXUS oxygen sensor. The aftermarket one's *can* work and *may* last a while, but the factory parts have specific parameters that usually are not met with the cheaper parts

-george

Mcon

iTrader: (1)

This sensor that I mention before and that I bought on eBay is a Denso Brand. I don't want to offend anyone with this I'll say. Do not misunderstand me please. Buy as told me a mechanical a day, Lexus make cars, not parts. Lexus support a few pieces or parts brand for Lexus cars and at the same time make more money. For me is a reality. Was a mechanical from Toyota Dealer that told me this and I think also all company that make cars do the same. Mu humble opinion guys.