Gunnut

I have to believe part of my problem is the O2 sensor since the code re-appeared without starting the engine. How could a functioning O2 sensor sense a bad cat if it has not tested it by having the motor run?
As I said there has been no decrease in performance or mileage.
FWIW, I replaced the bank 1 post cat sensor a couple of months ago.
JimA

RocketSlug

Same code on my 2001 GS430. Took it to independent shop, they said it needed new cats. At $1500+ each, plus labor, I was not about to. . then the shop called me back and asked "How many miles on it?" I told them just under 80K, they said its probably still under the Federal Emissions warranty. Called the dealer, they weren't sure. Dealer called back, and I took it in for the first free cat replacement.

Got it back the next day, light was still on (on the way home from the dealer!) Took it back, said it must be the sensor. $400 and a day later, get the car back. Light comes back on the next day.

Trip 3, I'm like WTF? They replace the other cat. Its been a over 1000 miles and crazy Ohio weather (from 10-65F and 20" of snow and rain in a month) and the light is gone.

I still think the sensor was fine but they don't want to admit they misdiagnosed it. And $400 for a $85 part makes me furious, but one guy owns all the dealers for 100 miles. We pay more for parts and service here in Columbus,Ohio than they do in Dallas or Los Angeles. I know that for a fact because I call Sewell and Longo Lexus for parts!

Gunnut

I cleared the code again this morning before coming to work. It has not lit back u as of yet. I've driven 50 miles today so far. We'll see how long it takes to pop back up.
JimA

Deception

iTrader: (1)

I pulled the same cold p0430. I noticed that the car exhaust fumes does smell worst than before. i have 140,xxx miles on the car. i cant be too sure if its a leak or cat and o2 failure. but i did noticed that the cel only came on, on the cold days. and then warm the next day. i also noticed that i saw condensation from the pipes were its leaking. so i assume its a exhaust leak for now. im gonna change to headers and downpipe anyway. i'll see if it reoccurs again.

3UZFTE

Don't know if this helps, but i figured i'd try to help. P0430 code is Catalyst system effciency below threshold (bank 2).
Step 1. Check for any other codes present.
Step 2. Check for gas leak on exhaust system.
Step 3. Check bank 1 and 2, sensor 1.
Step 4. Check bank 1 and 2, sensor 2.
Step 5. Replace 3-way Catalytic converter.

gtmax

My check engine light has started to come on sporadically. What pisses me off is that it started doing this just after i got the 90K mile tune-up. Can an independent mechanic figure out the code, or do i have to go to the dealer?

Does the light come on after certain miles automatically? I'm at 96K+ miles.

Thanks in advance!

Nosexnolex

im out of luck. Passed 80K and the car is not covered anymore under warranty I am taking the car to lexus and will check what it is for sure.

alenga

I have a 98 gs300. I got the same code P0430 and took it to an independent shop. I was told that I have a bad cat converter and told me to replace it. I called the dealer for a price and costs almost $1,000 without labour. I decided to take it to firestone and paid $102 to check it again. They told me the same thing. I bought the cat converter online and got it 2 days ago. Unfortunately, the check engine light went off by itself before taking it to the shop to replace. I am really confused and don't know what to do. Shall I return the cat or go ahead and replace it? Any help will be appreciated.

GS4_Fiend

iTrader: (22)

Few ways to check the cat is bad physically..
- Use a rubber mallet and lightly tap the cat and hear if it's rattling inside. If yes, the honeycomb is broken inside.
-Use a pyrometer and check the temperature of the inlet and the outlet. The outlet is suppose to be 10%+ hotter than the inlet. This method is a very efficient test.

If all of the above is okay, the post oxygen sensor could be given a false input and that could be the culprit also.

Hope that helps.

alenga

GS4_Fiend,

I thank you much for the quick response. I am going to do the test as you said. But, I am not sure which one is inlet and outlet. Thanks again.

CPMD

iTrader: (2)

Hey, I had the same problem. Do a search under my name to see the whole story. Also, you made a mistake going to firestone to have it checked. It's o.k. we all make mistakes once in awhile The CEL will go on and off, as it did for me. Where in OH are you? If your in the Cleveland area, go to Allstar Discount Muffler 216-671-8900 they do an awesome job for cheap. They will also read CEL's for free.

alenga

cpmd,

I am in cleveland. I will check them out tomorrow. Thx again.

GS4_Fiend

iTrader: (22)

Inlet is towards the engine. And outlet is going out to the mufflers.

CPMD

iTrader: (2)

No problem man...If I were you, I would return the cat you bought online, and just go through Allstar muffler. They put in their cats and warranty them, all for under $300. I can't remember exactly how much it is because I didn't have to get my cats from them (mine were under warranty so the dealer replaced it), but I know it is crazy cheap, and they are really good. That would be the best bet. Get there early in the a.m. when they open b/c there usually is a line lol.

alenga

cpmd;

I went to Allstar to check them out this afternoon. They were able to check and found out that the cat is bad. Unfortunately, they have to order the cat from somewhere for $675 and additional labor. I thanked them and left.