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GS - 2nd Gen (1998-2005) Discussion about the second generation GS300, GS400 and GS430 (1998 - 2005)

help with p0430 trouble code

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Old Mar 4, 2014 | 08:34 AM
  #1  
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jaynic1234
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From: rhode island
Default help with p0430 trouble code

Hi I have 02 GS300 with a p0430 code I have had 2 02 sensors replaced as well as a used manifold . I am being told it could be a 3rd converter help please .
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Old Mar 4, 2014 | 10:21 AM
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Driver side upstream, if you have replaced both already, it may be time to do the cats,
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Old Mar 4, 2014 | 11:42 AM
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thank you for your reply I replaced the two up front should I change the 1 in the rear ?
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Old Mar 5, 2014 | 12:53 AM
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Yes change the rears as well. Although it says it would be upstream a bad O2 downstream can give off the code as well.
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Old Mar 8, 2014 | 09:16 PM
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look if you have a exhaust leak ( even a really small one) at the cats flanges. I had the same codes p0430 and 431 and the really small leak there was enough to trigger the code. 2 gaskets and the problem was gone.. It's worth a look before you start changing cats lol
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Old Apr 5, 2014 | 02:58 PM
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Originally Posted by JFBPhoto
look if you have a exhaust leak ( even a really small one) at the cats flanges. I had the same codes p0430 and 431 and the really small leak there was enough to trigger the code. 2 gaskets and the problem was gone.. It's worth a look before you start changing cats lol
say there was a leak.. or tiny crack under heat shield. would a mechanic be able to physically hear it? under load / idling?

i have had a few of them check but no one seems to think its an exhaust leak..

2006 lexus gs430
code: p0430
loss in gas mileage (big loss)
mileage: 90k
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