Gannet

I think you will find that OEM cats are quite expensive. The Toyota dealer has access to the same TIS system with the service diagnostics that the Lexus dealer uses. If changing out the "cheap" parts doesn't solve it, I would take it to the Toyota dealer and have them run through the diagnostic steps prescribed by Lexus.

ecuwil

As a followup question, if it is the catalytic converter should I replace it with OE? Granted, I do not believe I can complain about 80,000+ miles out of a cat, but this seems to be a common issue. If needed should I replace with a cat that might not create issues in the future?

To that point, I have the same question for the o2 sensor. Although I have already ordered the OE o2 sensor is there a more reliable sensor? Why is the 430 so hard on o2 sensors?

Lynzoid

It's not hard on sensors.... My upstreams have 240000kms on them, my downstreams are same! They may fail electrically, but it's totally different DTCode!!!

And again - NOTHING TO DO WITH UPSTREAMS!!!
P0420/0430 - Catalyst Efficiency Below Threshold bank 1/2!

I think you can get aftermarket cats, as they are basically the same and OEM ones are hella expensive.

BradTank

Federal law mandates that manufacturers have to warranty their catalytic converters for 8 years or 80k miles. You may have just missed your warranty, but it might be worth seeing if a Lexus dealer will play ball, though it's probably a longshot.

I would NOT recommend buying an OE catalytic converter, you're talking about something like $1,500 installed. You can buy an aftermarket one from a company like Magnaflow for around $300 and have an exhaust shop install for around $100.
http://www.rockauto.com/catalog/moreinfo.php?pk=3852588

If it were me though, after I made sure there were no exhaust leaks or clogs, I'd probably just throw an O2 simulator on and call it a day. All the downstream code is saying is that your catalytic converter is not working at the efficiency it's supposed to, it could just be just slightly under performing. It's not telling the car to change the way it drives in any way.

Lynzoid

I second last poster in almost every word! Magnaflow is great.
But it does change the ecu fuel maps Turns out, the ecu program will default to 'safe' mode, if 'emissions monitor status is NotOK' - and DTC P0430 certainly prevents it to be OK status. I own a toyota scantool =)
Anyways, when it silently defaults to 'safe' maps it basically means the power output will drop and consumption will rise, thus making 'uncontrolled' emissions 'safer' for 'environment'...
I also drove for about 3 month trying to neglect the p0420(and shortly after +p0430) just to start noticing the loss of power and higher consumption (not as high as when UPstream sensor gives out on EFI cars but still). That pushed me to go radical and hollow out cats and install 'o2 spacers' (eg this one http://www.ebay.com/itm/2-X-O2-OXYGE...cf709d&vxp=mtr). And yes, for LS430 you will need angled spacers (i found it out the hard way.. had to reweld crapload of exhaust metal..).

ecuwil

Lynzoid: thanks for the link to the o2 spacers. I appologize for my ignorance, but should i install the spacers along with the new o2 sensors. It sounds like if i install the spacers i would not need to replace the cat because the spacers "fool" the ecu? If i understand the purpose of the spacers i would not even need tbe new o2 sensors, just the spacers.

Lynzoid

Yes, you can just install the spacers with new/old sensors and they will fool ecu. But at some point cat innards will begin to melt and seriously restrict exhaust. just fyi.

toyo

Excuse me for my ignorance here. 2 people have commented that a CAT going out at 80K miles is nothing uncommon. I'm sorry, but this is absolutely nonsense. I would love to see a poll on who all has had to replace the CATs at 80K. Unless there is an inherent defect I can't see it. This engine is too clean running with it being ULEV to be ruining CATs.

ancdmd

Agree 100%

jay33

95k on 2002 LS430. No issue with Cats or O2 sensors. Everything is still all original and working fine.

Lynzoid

Usually cats go out soon if there's subpar quality gasoline was used for a prolonged period of time.

LS400TX

Man I understand what you mean, I totaled my LS400 last year, but I can tell you after I bought my LS430UL last year, it's no way to go back. You'll get it ironed out.

ecuwil

Update-new upstream o2 sensor installed and the check engine light is off.

I will install the down stream sensor and spacer tonight.

toyo

Myth. Cats can and will go bad if an engine is not tuned properly, leaking injector, etc. It's the raw, unburned fuel that will ruin a CAT.

ecuwil

One additional update, Lenzoid, the spacers you sent the link for do not fit my 430. The spacer hits the bottom of the floor pan, I will send the ones I ordered back to the ebay seller.

Can anyone recommend O2 spacers/simulators that they have installed?