Cat problem?

infj23

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#1
Make
Lexus
Model
ES 330
Year
2005
Miles
368000
Engine
V6
Bought this car with 258000 miles on it. It now has 368000 miles. It has occasionally thrown a P0157 code. now I'm getting that code plus 3 pending codes: P0174, P2198, P2A03.
No noted change in fuel economy. Ever so slightly rough at idle.
Looking at scan tool:
O2 sensor 11 stayed around 3.2 volts
O2 sensor 12 stayed around .5 volts
O2 sensor 21 stayed around 3.3 volts
O2 sensor 22 stayed around .2 volts
Bank 1 sensors did not cycle between 1 and 0 volts but stayed over 3 volts.
Similar readings both stopped revving to 2000 rpm and driving steady speed 60 mph (also about 2000rpm)
Wanted to post videos of what my scanner looked like but the files were too large to upload.
Any thoughts? Bad cats is my guess.
 

grcauto

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#2
Does that thing have O2 sensors or lamdba?
 

infj23

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#3
4 O2 sensors. Two on each side. One in front of the cat and one after.
In my initial post, O2 sensor 11 is side 1, before the cat. Sensor 12 is side 1, after the cat. Same for 21 and 22.
 

grcauto

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#5
That's not a typical O2 sensor. That a wide range sensor that allows for leaner running under cruising conditions. For the Toyota/Lexus Lambda 3.3 is normal.
 

infj23

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#6
I have continued to check the data as I run and idle my car. With the downstream voltage steady at 0.00, my guess is a bad cat.
Changing that cat looks like a pain for a shadetree guy. I wonder what the mechs here think about trying a bottle of Cataclean or a gallon of lacquer thinner in the gas tank. Any chance either of those things might save me the time and effort to replace a cat in my garage (not to mention the money!)?
Thanks!
 

nickb2

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#7
or a gallon of lacquer thinner in the gas tank.
Highly do not recommend this.

Have you tried some infrared heat test? Or maybe a back pressure test? Steady 0 volts would be an abnormal reading and probably lexus trouble shooting would steer you in a circuit check of o2/lambda sensors affected.

The reason I highly do not recommend lacquer thinner, is the fact that the throttle body has a lacquered finish applied by factory, and this thinner will probably destroy that finish and cause future problems such as sticking throttle plate, IAC response will diminish and set you back even worse than you are at right now.

My sister has a IS 250, 2007 model. After cat sensor on driver side coded just like you. Almost exact code scenario you are describing. No switching whatsoever. The wiring to that sensor I found to be cut on frame rail under seat. I replaced the heated o2 sensor. What a job that was. Had to remove whole center console, driver seat etc just to get to the sensor connector located beneath carpet and the parking brake assembly. In retrospect, I would have preferred it to be a bad cat, but scan readings just told me from experience, this was a circuit issue, not a mechanical problem at all such as a vac leak on that bank or a plug/cooked cat. Your model is not as difficult as the awd drive 250.


Does that thing have O2 sensors or lamdba?
@grcauto , actually, it has both. I think they call them air fuel ratio sensors/lambda sensor for the post, and the proper terminology for the aft is heated o2 sensor. So you are right in this terminology. Thx for that, because the difference in terminology is confusing for the beginner. Good catch. ;)

Bank 1 sensors did not cycle between 1 and 0 volts but stayed over 3 volts.
The malfunction threshold for your car is 6 or more.

So I am not surprised it coded P2A03. Of note, on generic scan tools, unit conversion is done in mode 6. I am assuming you are using a generic scan tool. However, if any other o2 related codes are present, which is your case, you must resolve those ones first. From some night courses I followed, I was typically told to ignore these codes as they are mode 6 codes and they will always appear when the ECM cannot go into closed loop and do its final drive cycle for the o2 readiness monitors. I hope I am making sense to you here.
 

nickb2

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#8
Here are some pdf's to help you along with this trouble shooting process before throwing expensive parts at this car when in fact, it may just be a bad/loose connection, pinched/cut/short to ground/voltage, etc.

Of note, in the following pdf which is for P2A03, page 1. No mention to suspect a bad cat at this time. First thing to check!! Circuit. Last thing to suspect, ECM.

For others who fall on this thread, here is a snap shot of strategy to follow. Screenshot (292).png
 

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nickb2

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#9
This following post is not meant for the OP, but more directed at the site in general. Specifically directed at grcauto and Billr.

I hope the following thread here will prove that I listened to you and took both your comments very seriously. I came to the inevitable conclusion that lately my posts were some times not helpful, lacking in professionalism and below a standard I had promised to deliver to this site. I became complacent and took this site for my personal playground and did not observe forums rules.

For this I thank you both. I also hope my recent past behavior will not set you back on creating a bond with me here in the internet world of BAT auto, as I love the idea behind the reason of existence of this site which I am still assuming is to help others free of charge and try to make this world a better place one advice at a time.

From what I see here, you and Billr, and many others here with such a wealth of knowledge would have made a great mentors for me if we would have met on a job site. But now, I am 43, and it is my turn to mentor other young men in this trade, and your comments awoke a positive trend in my head.

Since I like posting videos, I think this one is more representative of who I really am.

 

billr

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#11
I'm going to reply in the Lounge, but I will give you a hint: that video above is great!
 

infj23

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#12
nickb2,
Thanks for the reply. I carefully checked the wires coming out of the Bank 2 Sensor 2 O2 sensor. That set of wires is about 9 inches long, so not much. I did not see any problem areas. All of wires/insulation looked good and the connector was securely attached. I cannot imagine where I would look or how I would find additional wiring I might need to check. Any guidance there?
By the way, the exhaust smells different. I park in my 2-car garage every night so I get a whiff of exhaust every time I get home. It stinks worse now. Now exactly sure how to describe it, but it smells worse. Does that mean anything?
This weekend, I will try to do the infared thermometer check. I'll post back my results.
Thanks to all!
David
 

nickb2

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#14
If so, that is indicative of bad combustion. Raw unburnt fuel going through the cats. At this point if that smells exist, probably cats are half cooked anyway, the smells proves that, but even if you put new cats in there, they will cook again and still give off that sulfer bad egg smell. Much like if you just burnt a full book of matches.

Not my writing, but conveys what I am trying to say.

Another common smell is similar to rotten eggs. Unless you have rotten eggs in your car, this smell is a burning sulfur smell which is a clear symptom of a catalytic converter problem in your engine, or damage in the emission control system. It may also mean that your engine is running with a rich air/fuel mixture
 

infj23

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#15
The smell is not the rotten eggs/sulphur kind of smell. Not exactly sure how to describe it, but it seem to be just a heavier does of the usual smell. Maybe I'm imagining it because I know I have an emissions problem somewhere. Perhaps best to say it smells "more" rather than "worse."