Chidude23

I've been having these problems with p0420 p0430 took it to the dealer they told me there are holes in the y-pipe and that I need a new one at 78k miles(Thought the dealer should have replaced it being that the cat is connected to the y-pipe). They quoted me like 2k, all this due to the heat shield so I ended up taking it to a muffler shop and they cut off a piece of the pipe and replaced it . Thankfully that fixed the problem I was do for emissions and it passed. But at 95k the light came back again noticed the car losing little bit of power again. I ended up ordering a downstream sensor to see if this is going to help out the problem. Have not installed it yet, and SHOULD I also replace the gaskets.

XxGoKoUxX

You're hard at work already, keep us updated lol!

striderg3

i'm going to have my gs430 06 with 901xx miles also inspected for exchuast leaks.
when your codes came up, did you have ONLY the check engine light on?
or check engine + the trac off light and the (!) yellow exclamation mark next to CEL also come on?

anyways did the downstream sensor fix it? and my car is only giving me error p0430 bank 2.. not the 20 code. what's that mean? only one side is problematic? im guessing bank 2 means passenger?

hope your problem was resolved. hopefully mine is too.
im hearing replacing a CAT converter is gonna mean the car will NEVER perform the same..
someone told me this on the phone and he said if its an aftermarket CAT forget about having the car ever perform the same.. dunno if that's true?

XxGoKoUxX

That's not true.... A catalytic converter's purpose is MAINLY to convert bad gases to more o-zone friendly gasses.....

Whomever told you that is a little ...

striderg3

So should I be able to get away with not installing an OEM CAT if it turns out my cat is what's causing the code? Few people say they installed Magnaflow cats and are happy.. Can I do the same!? And do the O2 sensors need changing when the cat is changed? Even if they are functioning as they should?

I'm thinking of giving the car to toyota to inspect. There aren't many good shops that I feel I can trust with telling me what's actually wrong. And toyota seems to say they'll diagnose it for $50 or so.. Not bad I guess.

Chidude23

Which cat is it the one with the Y-Pipe because I am considering changing mine.

charmz

I also have this P0420 code along with P2198 (O2S STUCK RICH 2/1).

I replaced my y-pipe and reset codes and going to wait and see what happens.

My car is 2006 GS300 with 200,000 kms and burns about 1 litre of oil ever 800-1000 kms.

It showed CHECK ENGINE and CHECK VSC.

Chidude23

Charmz thank you and keep us posted and the Y-pipe you replaced was it OEM and did you also have a loss of power during that whole problem.

charmz

No real loss of power that I noticed.
It was not OEM replacement, my mechanic fabricated new piece from the manifold to the cat.

Chidude23

I'm hoping the loss of power is from the y-pipe cat (it goes away then it comes back). Im bout to end up getting this this done OEM thank you

charmz

Our cars have 3 Catalytic Converters....

One on each exhaust manifold (2) and one on the mid pipe (1)?

Is this correct?

Sewell Parts List
17104 - MANIFOLD SUB-ASSEMBLY, EXHAUST, (RH - RIGHT / PASSENGER SIDE) = $1050
17105 - MANIFOLD SUB-ASSEMBLY, EXHAUST, (LH - LEFT / DRIVER SIDE) = $1050
17410 - MID PIPE ASSEMBLY, EXHAUST, FRONT NO MARK = $1760

Schmexus

Should be 4. There are 2 separate cats on the midpipe section and 2 right after the manifolds.

charmz

So after 50 km's my CHECK ENGINE and CHECK VSC are back on...

Did a scan and show codes P0420 Bank 1 again.

How do I determine which cat this is?

designo

iTrader: (6)

That's correct, our cars have two primary cats and two secondary cats. Fortunately, the secondary ones have O2 sensors only.

XxGoKoUxX

I don't think the o2 sensors need any changing, AT WORST, you'll need the adapter that Schmexus used (90 degree adaptor) to compensate for the free flower of the magnaflow catalytic converters.

Yes, the Magnaflows will work


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