Jonathan o

Hey! Im fearly new to CL. I have a problem like to see if any of you have had this happen. I have a
99 sc400 all maintnace up to date done by my local lexus dealer. The CEL came on took the car in and I was told bad 02 sensor had the car fix $250 CEL was off. Two weeks after that CEL is back on took the car back to lexus and they told me that I had a bad catylitic conv bank2. They wanted over $900 for the part and 1hr labor that is just one. So I got a set of high flow cats from stillen had them put on at my local muffler-shop all new gaskets and all new o2 sensor all 4 of them.
light was off for about a month or so. CEL is back on again went back to lexus told them what I did and the tech told me that I wouldn't had gotten after-market cats put on this car. Can any one
shed some light on this mater "any help will be greatly appresiated". Oh! the code that the car is puting out is p0430. Any help please that CEL is anoying spacialy at night.

GliTCH

oh i know man tell me about it. mine is on too and i hate driving at night now. i dont know what the deal is but aftermarket stuff does that.. its not within spec so the sensor thinks the stock part is failing. i have no idea where in the cat they put the sensor or what exactly triggers it. if the cats you put in are smaller than the stock units though or allow for better airflow, then maybe the exhaust exiting your catayst is way dirtier than the specs allow for. that would cause the light to trigger for sure.

Jonathan o

Glitch the crazy thing is that the light will came ON and go OFF all by it self. EXP( the light was ON all last week and sartuday at about 6 pm on my way home I looked at the speeedo and the light is off . I when out sartuday night, sunday and light didnt come ON till monday morning on my way to work. What you think about that. Oh! you know whats funny the CEL came ON just as I was going pass the lexus dealership I tell you sometimes I feel like this car is ******ing with me.

GliTCH

if you got new O2 sensors, cats and the light still keeps coming on and off.. then the ECU probably can't handle the new air/fuel readings coming from the high flow cats and thinks something is wrong... sometimes they might be within spec and sometimes not.

are your replacement O2 sensors from stillen or lexus?

if they are lexus ones, i would call or email stillen and see if they can get you O2 sensors that would give adjusted readings.. if they dont offer those, ask them if they know where you can get your O2 sensors recalibrated/modified. that would give the readings your ECU is looking for.. im only guessing that this can be done, ive never seen anyone do it or even thought about it until now. all the sensor does is send a voltage

i think the easiest (and most expensive) way to get rid of this though would probably to get an aftermarket ECU for the car.. would probably be the best way to take advantage of your new high flow cats too

Dx3

iTrader: (13)

What does this mean?

Jonny

Jonathan o

The CEL will came ON and stay ON for a few days and It will go OFF and stay OFF for 2-3 days back and forth is crazy.

Jonathan o

The o2s are lexus all 4 of them. The car runs great is just the CEL is anoying. Thankx will look into it I should have done that. Will call stillen and talk to them about this

JspecSC3

iTrader: (4)

I drove around in my friend's old SC400 with the loudest exhaust you will ever hear. Anyway, he had his check engine light come on when he had gutted out his stock cats. He had it checked and turned out to be a bad O2 sensor. The good thing about Lexus (toyota) is that our motors come with a sub-O2 sensor so the motor still functions correctly. He had bought the replacement O2 sensor but never had the chance to put it in before he sold the car. So what im trying to say is the exhaust modification could have done it. Might not be. Have it diagnostic checked so the shops can go straight to the problem instead of guessing what it might be.

Jonathan o

That is what I did took it to lexus and had the car diagnose by lexus and they told me the cats is the cause of my problem and, I know 9 times out 10 they will be right. I'm looking for a way to keep the Hi Flow Cats and get the CEL to go OFF. ( Have my cake and eat-it too) Let see what happens I made a few phone calls. Now I will wait to see what I can do about it.

Jonathan o

"Glitch" I took your advise I put a call into stillen a told them what is the problem I'm having and they are going so see if there is away around hopefuly there is. I just hope it is not too costly. I'm looking to buy
a house in the next 3-4 months and you know how that gets. Oh! no o2s simulators for the sc400. The guys at stillen will call the maker of the cats to get specs and try to find a way around it. I'll keep all you guys posted. Thankx for the help MAD PROPS

JspecSC3

iTrader: (4)

Ohhh good luck dude! Let me know how it goes. I always wanted to know how to solve that problem.

Jonathan o

Ok! Guys finaly spoke to the stillen tech and He said to go to a muffler shop and have them add a resonator to it. It will quiet the car a little "which the car is not loud at all, well maybe a little. But it will slow down the flow just a bit. Will try to get it done ASAP. Oh! the code that I' m getting is p0430.