mwwilliams

I have a check engine light and VSC errors on the dash and my local repair shop said my Cats are bad and will cost me $1600 for replacement. The car runs fine. No power loss that I can tell. Going to check it out more today. What would be recommendations?

I was thinking an aftermarket exhaust but had heard it might mean the engine module may need to be re-tuned for the new exhaust. Just wondering if that is true as well. Something like this:

http://pacesetterexhaust.com/supra-l...converter.aspx

Error Code PO420 CAT Efficiency

LentoGS300

I responded to your other post in another thread concerning this matter.

Mcon

iTrader: (1)

mwwilliams,

Please check this thread before you lose your all exhaust cat. This what happen to me with the same code. check your Mid pipe that in there is a small cat also and that small cat was my issue.
Also, What year is your car? 1998 to 2000 use a different exhaust manifold that the 2001 to 2005.

https://www.clublexus.com/forums/gs-...-problems.html

This item on eBay is for 1998 to 1999. 272098282998
This one is for 2001 to 2005 eBay item number: 252249493833
Check it out and good luck.

Mcon

iTrader: (1)

Also, sometime, sometime is your O2 Oxygen Sensor. Is cheap to buy and install the O2 Oxygen Sensor first.

mwwilliams

Sorry, mine is a 2003 GS 300

Mcon

iTrader: (1)

So mwwilliams,

You need this item number: 252249493833 that is 2001 to 2005.

czr73

I hate it when mechanics (including want-to-be mechanics) jump right into "it's the cat".

Any smart mechanic goes through a troubleshooting process first to isolate the problem and verify the fault.

Put a ODBII code reader to confirm this:

From experience, your ECM is throwing error code P0057 which is a O2 sensor, bank 2, sensor 2. Easy fix.
Your fuel mileage will suffer greatly if you don't replacing soonest. Go buy a Denso 234-4603 / Toyota# 89465-30490 O2 sensor. That's the OEM model.

Or you might have an exhaust leak. Replacing the cat is a big job and expense. So do that as last resort.

i hope this helps.

Czr =)

Mcon

iTrader: (1)

czr73,

I want to start to say that I have a question for you before responding to your comments that are you made with respect to what are hate by a mechanic. You read the whole thread before making your comment?? Do you?? I began by saying what had happened to me before with that code. Then I was talking about what could be happening to my vehicle. Because that's what happened to me. The cat in the mid pipe began to clogger and that was the RASON why my car gave me the code. I have over 40 years of experience on TOYOTAS AND LEXUS. To come one baby to tell myself I'm saying or pass myself off as a mechanic. Learn from the experience of life and what happens to others and live better. And above all to love the person more human beings around you. God loves haters 2. God Bless You.

bruceb58

CZr73 is totally correct. More diagnosis needs to be done before replacing any parts on the exhaust system, especially any of the cats.