qgoat

Yeah I would try an o2 sensor first. Took my car to the dealer for that code and they said it was the cat so I bought a cat and had it installed and still got the code. replaced the o2 sensor after that and the code went away. I would say if you are not having any driveability issues (i.e. loss of power at times)or any funny smells from the exhaust, then it is more than likely the sensor.

Lexmex

You can have the electrical resistance checked on the O2 sensor itself or if you are so fortunate, have a gas analysis test (like an emissions test) run on the exhaust. I have had my OEM cat and one of my precats get eaten by gas I used out in the boonies down here.

minla007

wow...seems like alot of dealers are getting ppl to replace their cats, when its actually an o2 sensor issue?....ouch!....paying all that money to replace cats and problem still persists?

seems like a common tactic for dealers to squeeze some xtra loot out of the customer...hmmm....

i dont feel any loss of power, just the stupid CEL light is on and my emissions inspection is coming up soon too....otherwise, i wouldnt really care....drives fine

Lexmex

Well, there is series of instructions they usually (at least I hope) follow straighout of the manual, which I have in book form for my RX300, and they show to check the resistance on that code.

However, I know from experience that cats can and will go bad down here due to high sulfur in the gas along with other impurities, something I will be glad to finally relieve myself of when I go home to Florida next month.

qgoat

If you should need a cat, you can get it at ******************.com for about 200$ and just get your local muffler shop to install it for about 50$. Thats what I did.

BossGS4

iTrader: (2)

Don't the GS400/430s need TWO cats which bumps the bill up to $500 ...ouch!

minla007

yeah the gs requires 2 cats...but even 2x $200 + labor would prob be cheaper than $1800

what brand of cat converter did you buy from ******************.com? i have bought from them before, but had a bad experience...

is there any major difference w/ getting an aftermarket cat vs. OEM cat? any fitting issues?

qgoat

I dont remember the brand but it was supposedly a direct oem replacement. It was over a year ago and no problems as of yet. I only replaced the passenger side cat. I would definately get the part number from lexus and have them cross reference the number to make sure you get the right part.I learned that the hard way when I had my volvo.

TRD911

Just cut them out... I know all the enviro hatters will come out.

I think that the car companies put them in for the GOV. And they should take are of them..

Most of us are smart enough to outsmart the ECU.

I did it on my 00.... it was easy...

cost about 30...


BTW... I am NOT interested in haters....... and ohhh.. this was the post cat.. as all they do is monitor catalyst performance..... do not try to bypass your precat O2 as they deal with fuel mapping.. what I call engine mapping.


BP

minla007

yeah good idea, but unfortunately i can not do it, or else my car will not pass emissions inspection and if i cant pass emissions, i can not register my car....doh!

minla007

so to follow up....last week on friday...my CEL light went off....so i took the GS4 into the emissions station to get my emissions check done and it passed!!!

so if my cats were bad, i don't think i would've passed emissions right? or could bad cats still allow me to pass emissions?

today, the CEL light came back on after a few days of it being off. good thing i got emissions done before it came back on.

so its prob bad o2 sensors or loose intake manifold gasket...car still runs fine

UncleRay

iTrader: (2)

I had the same problem for about a couple of months. Changed the O2 sensor on bank #2, and the CEL code never came back!

StasGS4

iTrader: (1)

Which O2 sensor did you change UncleRay? Upstream or downstream of the cat?

GS4_Fiend

iTrader: (22)

The cats are not suppose to go bad unless the car burns oil, misfiring, etc. which clogs up the cat. If I were you, I would give it a shot and change the post oxygen sensor. Much cheaper than replacing a cat. GL!

StasGS4

iTrader: (1)

Thanks for your help!!!