peafarmer

My 2003 LS430 has 80,000 miles, and recently started throwing codes for a fouled catalytic converter.

I started noticing noise from an exhaust leak shortly thereafter. I got under the car to scope out the cat replacement, and see that the driver side gasket is totally blown.

So, I was wondering: cats normally last more than 80k. So, I am considering just replacing the gaskets. How likely is it that the fouled catalytic converter code is really due to improper flow caused by the exhaust leak?

I don't want to be foolishly cheap, but don't want to throw away perfectly good cats if there is a chance that they are still ok.

Thanks,
Andy

Legender

I would just replace the gasket... the sensors are looking for a certain oxygen/gas/exhaust mix...when you have an air leak in the exhaust it messes with the sensor readings...and all he knows is the converter is out... I'd fix the gasket first and believe that will fix your problem. My two 430s have over 130k with the original cats... I think they last a long time...

Boomer01

I have 180K miles and just started receiving the bad cat code. I read on here that people had similar problems which turned out to be small rusted holes in/near the "Y" pipe. They bought aftermarket Y pipe and cat and the codes were gone.

tjwashow

hey- i have this same code now for the passengers side, i brought it my guy and we tried replacing the gasket and sealing things back up. i have 130k miles as well. DID NOT WORK FOR ME. code came back on about 30 miles later. I am going to just buy a cat for it and be done with it. I am not going to go with a stock cat tho. Does anyone know any good replacement around 50-100 bucks?

AppleJuice

Same thing happened to me. I had an exhaust leak. Got an exhaust place that made me a new Y pipe. I disconnected the negative battery terminal to erase everything and the CEL hasn't come back yet. *knocks on wood* ...been about 500 miles now

tcr101

iTrader: (2)

By chance was the code a p0420?

tjwashow

my code was a p0430, im gonna take it my mexi muffler shop and have them dig around somemroe to see if they can find the exhaust leak.

LEXI432003

can you update if you got a new cat and if that fixed the prob? don't want to replace the cat if I can just fix a leak or replace gaskets. thanjs

Lavrishevo

iTrader: (1)

420 and 430 are cat efficiency codes. First check for leaks. If no leaks an experienced mechanics and tell if it is the 02 sensors or the cats.

Spork11

I had the engine light on, car running fine. Checked the code with a bluetooth code checker, got a P0430. Thanks to all the help from these fourms, realized it was likely the exhaust leak that everyone pointed out.

Not having a lift or welding ability, looked for a muffler shop that had good reviews. They didn't even put the car on the lift after specifically asking them to check the passenger side (bank 2) pipe at the heat shield.

They just ran the code, said it would be $2,300 as the converter needed to be replaced and that the parts need to come from the dealer. If I had $2,300 I may have just had them do it, doubting the tons of people who said otherwise.

Instead, took it to another shop, where the guy put it right on the lift and immediately found the leak. It was exposed and easy to find while the car was running, put his hand right up where the front of the heat shield met the pipe. He also noticed the clamps were rusted, and that the driver side (bank 1) looked like it would soon have the same issue.

He fixed both the Drivers' and passengers side for $80 with new clamps, which fixed the engine light. Passed emissions and saved $2,220 over just trusting the first opinion.

Can't thank everyone enough for sharing their experiences. Without it, I would have spent a ton of money on something that likely wouldn't have fixed the problem.