jmsed

We have a 2001 LS430 UL, 220K miles. We had a lot of different places that were leaking oil and decided to have all of them repaired. Rear Main Seal, Front Crankshaft Seal, Lower Engine Oil Pan, along with a timing belt gears idlers ect.. replaced by local Lexus dealer. Next day Check engine light appears. Lexus Dealer says the error code said bank 1 catalytic converter is bad and needs replaced.


The real questions are, could they have done something when dropping the Y pipe when replacing Rear Main Seal that could have caused the error?
Or now that the car is running like new it messed up the o2 sensors. They are chalking it up to being old.


Does anyone have any clues on how difficult to replace catalytic converter DIY. I got the tools and skills, more curious on the amount of time. Since I have to pull the Y pipe I intend to replace both.


Any help or advise would be appreciated

Bocatrip

You haven't mentioned if you just purchased this car or had it for awhile. I assume you have spent some significant money fixing these leaks.Can't answer your questiion about the y pipe but you own a old sophisticated high maintenance car. With those miles repairs are on the horizon especially with the UL which is the more expensive LS430 to own. Sorry I can't answer your question but good luck with your baby. ..... but be prepared to spend. Good luck.

Othic

What was the code? As long as theres no rust its easy to take out. If the nut seizes on the stud.. different story. That happened on my GS430. Even with all my tools and a lift it was a pain in the *** to extract the broken stud.

jmsed

Thanks for the reply. They didn't tell me the code # just that it was the front c/c on bank 1. I can call and ask for the exact code # if they will give it to me. As far as the work goes, I used to work in a muffler shop and know the fun involved when busting a manifold stud. Thankful for them left handed drill bits sometimes. Hopefully with all the oil I had leaking the studs are lubed up. Could you guess how much time with breaking a stud?

Lavrishevo

iTrader: (1)

If the O2 sensors have not been replaced they are overdue. First off. Is it the pre-cat or post cat O2 sensor? Both can be had via RockAuto for a lot cheaper then the dealer. Post cat are just sniffers for the cats. If you have an exhaust leak it will trigger 420 or 430. Get the codes read and report back.

Othic

I usually charge an additional hour if that happens. Usually it'll take me the full hour. Either the studs are hardened, or my drill bits just suck lol.

P0420 Catalyst System Efficiency Below Threshold (Bank 1)

Detecting Condition
Bank 1 catalyst deterioration level exceeds malfunction threshold
while vehicle is being driven under specified conditions (2
trip detection logic).

Trouble Area
TWC LH (front catalyst) and front exhaust pipe (rear catalyst)
Gas leakage on exhaust system
Heated oxygen sensors

I would check your receipt and see if they billed you for 2 exhaust gaskets. If not, its a likely culprit that you may have an exhaust leak. I once had a 06 GS430 come in with this code and it ended up being a hairline crack in the exhaust near the downstream 02 sensor. Possibility, but I highly doubt it.

Arcturus

Yes these errors are well documented and are almost always due to a leak at the exhaust gasket or exhaust leak at the Y pipe. This is a common problem with this car and the cats almost never go wrong.

Take it to an exhaust shop, remove the heat shields, put it up on the hoist while running and check for a leak on the drivers side (bank 1).

If you find one, they can weld up the pipe or buy a new aftermarket Y-pipe one for around $200. Dealer part is around 1k. If it is really the cat, go aftermarket. I believe Magnaflow has one for around $350.

Othic

If it truly is the cat that's gone bad, you can go through route too. The resonators are pretty cheap.

https://www.clublexus.com/forums/gs-...the-gs430.html

Tom57

Agree it's likely a leak in or around the "Y" pipe that the dealer disturbed when removing / reattaching. Had the same issue many years ago on my '01 and made the dealer replace the "Y" pipe at their expense.

Coulter

Don't you love dealerships? I'm guessing you spent over $2,000 with them from the work you listed and they're basically telling you to pound sand.

It's too much of a coincidence imo, I absolutely think the work they did unsealed the exhaust in some way. They probably disconnected the exhaust to make room for something like replacing the rear main seal. Or they broke an exhaust that was already really corroded. They could at least own up to it and try to work with you.

As a side note, I personally would be hesitant to drop big money at a Lexus dealership on a car like yours that's probably worth $6,000 on a good day.

I'm not sure what sort of relief you're going to get from the dealership, but unless they're willing to make it right, I would get the exact code and then maybe take it to a reputable exhaust shop and get their opinion or try and diagnose it yourself.

Also, I know on mine I got a code and it was basically the same thing, the cat off the driver side needed replacement and no leaks could be found. I put one of those O2 spacers and called it a day rather than dumping that kind of money into a new catalytic converter. Haven't had an issue since.

jmsed

Thanks to all that gave me some ideas to look into, I will check all the ideas and reply with what the ultimate findings were. I'm almost betting they didn't replace the gaskets.

Tom57

The Lexus dealer had to "smoke the exhaust system" to determine where the leak was - they had cracked the "Y" pipe.

jmsed

Okay went to dealership today and the services writer assured me that they replaced the exhaust gaskets between the cats and the y-pipe. my bill does not show the gaskets on them and as we all know, the dealer just doesn't give away parts. he also said it was a p0420 code. Which many say is an exhaust leak. Going back to talk to the service manager. Thanks again to all that have given me ideas.

Boomer01

I've had the P0430 code (similar but different bank) and resolved it by replacing the Y-pipe. Initially had the muffler shop weld any holes he saw shut, but that only lasted a few months.

Othic

That's not always true. There have been numerous times I've forgotten to quote a gasket for a job and they say to put it on the shop ticket. Its just easier and their cost is much much.... much less than retail.

I would have them smoke the exhaust like Tom said.