02, Es300 Emission Test Failed.

[ICIcon]

Here's the breakdown of what I've done and what I'm trying to fix.

Got an 02, ES300 143K. CEL on.

Failed Emissions test with following 3 codes; P0420, P0430, P0446.

P0420 and P0430 are Bank #1 and Bank #2 Catalytic are both below standard efficency.

P0446 says the EVAP Carbon Canister is malfunctioning.

Got qoute from Lexus for bank 1&2 Cat replacement $1725, for Carbon canister $585.

Reset codes by battery disconnect.

CEL back on in 80 miles.

Autozone free diag of CEL showed same 3 codes.

Took it to a shop $40 for full diag. Told them I wanted to avoid catalytic replacement. They confirmed the codes. They gave quote for replace of both bank 1&2 Cats $1282. Said I could try the exhuast cleanout but were not too hopeful. They said to buy new gascap from Lexus/Toyota to clear P0446 code. They reset CEL.

Went to Toyota, bought new gascap $22.

CEL back on after 60 miles. Only codes P0420 & P0430 came back. Saved $563 by buying $22 gascap! :D

Got Motorvac service $99.50.

Ran hard on highway for 80 miles.

CEL back on after 92 miles. Codes P0420 & P0430 back again. :cries:

Looks like I gotta replace those Cats.

Anyone got some other suggestion???

[blk_on_blk]

Keep an eye on that P0446 code. I've got the same code popping on, and it's sporadic... will come on, then go off for a while, then come back on. I doubt a new gas cap will fix it (although there's the off chance it might), for the problem is usually in the charcoal canister. Someone on here said they ordered one for their ES300 through Sewel Lexus and it was only $240 +/- with $10 for shipping ( http://us.lexusownersclub.com/forums/index...showtopic=38899 ). It could aslo be the VSV, but it's so hard to tell. If you get the full canister, it has everything integrated and should catch anything that is causing the problem (assuming your lines are clean, clear, and unclogged/cracked). Just keep an eye on it and see if the CEL pops back on. Mine popped on, then turned itself back off, passed emissions fine, then came on again a week later. I think it's a relatively minor issue, but one that eventually needs to be addressed.

As to the cats, it sounds like they are clogged. You might have passed some bad gas (through your car of course :D ) that clogged both cats. Can't you just get some universal cats with the OBII ports and have a muffler shop cut and weld them in? I would think that would be significantly less expensive than factory replacements. I checked www.autopartswarehouse.com and they've got a big selection of cats under $100 each that are OBII compliant... they just need cut and welding. They also have direct fitments for $200-$300. I can't see labor at a good muffler shop being that expensive... maybe $100 to cut and replace. That would be about $300 total for the replacement/repair. Anyone know of a reason to go with factory cats?

[ICIcon]

Thanks, I'll keep an eye on that P0446 code.

There are 3 Cats on an ES300. The 1st one is part of the exhaust manifold on radiator side of the engine, the 2nd one is part of the exhaust manifold on firewall side of the engine. They both connect with a "Y-pipe" to the 3rd cat which is foot or so back from the "Y". The universal is only for the 3rd one. The 3rd one is not the one codes P0420 and P0430 are complaining about.

How I wish it was the 3rd Cat. Total cost at a shop with the universal would be $300. I'd be saving $1000. Not so Lucky. :cries:

Now I could gamble and change the O2 sensors, maybe they're misreading, but since I think it's the Cats I don't think I'm gonna take that bet. :whistles:

[jsinton]

I'm having the same problem with my Dad's 2002 ES 300: P0420 and P0430. It also has the TRAC and VSC lights on, which means there is a traction control failure.

I pulled the O2 sensors out, they look fine. In any event, a P0420 code and a P0430 code both at the same time DOES NOT INDICATE A CLOGGED CAT! The P0420 means the front post cat O2 sensor has detected a reading fluctuation. The P0430 code is rear cat o2 sensor has detected a reading fluctuation. The chance of the same physical problem occuring at the same time to both front and rear is almost impossible.

So there are other reasons why these codes might occur. They are:

* Leaded fuel was used where unleaded was called for

* An oxygen sensor is not reading (functioning) properly

* The engine coolant temperature sensor is not working properly

* Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe

* Retarded spark timing

* The oxygen sensors in front and behind the converter are reporting too similar of readings

So my problem, along with the VSC light, is leading me to believe I have either an exhaust leak, a stretched timing belt, or the VSC is leaking. Probably the VSC, but I don't understand the damn thing yet.

[jsinton]

I'm having the same problem with my Dad's 2002 ES 300: P0420 and P0430. It also has the TRAC and VSC lights on, which means there is a traction control failure.

I pulled the O2 sensors out, they look fine. In any event, a P0420 code and a P0430 code both at the same time DOES NOT INDICATE A CLOGGED CAT! The P0420 means the front post cat O2 sensor has detected a reading fluctuation. The P0430 code is rear cat o2 sensor has detected a reading fluctuation. The chance of the same physical problem occuring at the same time to both front and rear is almost impossible.

So there are other reasons why these codes might occur. They are:

* Leaded fuel was used where unleaded was called for

* An oxygen sensor is not reading (functioning) properly

* The engine coolant temperature sensor is not working properly

* Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe

* Retarded spark timing

* The oxygen sensors in front and behind the converter are reporting too similar of readings

So my problem, along with the VSC light, is leading me to believe I have either an exhaust leak, a stretched timing belt, or the VSC is leaking. Probably the VSC, but I don't understand the damn thing yet.

Problem solved.

I replaced the downstream O2 sensor with some OEM Denso ones. The original ones looked fine, but the resistance across the heat wires was a little low for spec. The new one resistance was 17 ohms, while the old ones were 14 ohms. It appears the P0420 and P0420 problem has gone away.

But the VSC lights were still on, indicating the VSC system was disabled. I was unable to find information about that. Finally, my Dad took the car to the Toyota dealer. Apparently they knew this problem. They said the VSC system needed to be recalibrated. They calibrated it and problem is solved.

So my theory is that somehow the O2 sensors being errant was able to corrupt the VSC system. I had disconnected the battery cable, but that didn't help. Only the dealer, apparently, could fix it.

[rlx101]

get OBD II --> USB reader from eBay and run diagnostics on your sensors, A/F mix etc. Its only 25$ and very useful in the long run anyway.

here is my first try with the OBD software and USB reader: link

Thanks, I'll keep an eye on that P0446 code.

There are 3 Cats on an ES300. The 1st one is part of the exhaust manifold on radiator side of the engine, the 2nd one is part of the exhaust manifold on firewall side of the engine. They both connect with a "Y-pipe" to the 3rd cat which is foot or so back from the "Y". The universal is only for the 3rd one. The 3rd one is not the one codes P0420 and P0430 are complaining about.

How I wish it was the 3rd Cat. Total cost at a shop with the universal would be $300. I'd be saving $1000. Not so Lucky.:cries:

Now I could gamble and change the O2 sensors, maybe they're misreading, but since I think it's the Cats I don't think I'm gonna take that bet.:whistles: