Code p0420 & p0430
05-12-16, 01:24 PM
#61
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you will notice that over the next few months the CEL might come and go occasionally... that is usually how it starts...
check your flange for leaks... i sprayed soapy water on it and it started to bubble... if you can get the bolts free and change the gaskets yourself, it's a $30 fix...
check your flange for leaks... i sprayed soapy water on it and it started to bubble... if you can get the bolts free and change the gaskets yourself, it's a $30 fix...
03-05-18, 04:09 PM
#62
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Success with O2 spacers
I finally think that I have solved by p0430 (occasional p0420) problem (2003 ES 300) by installing O2 sensor spacers on the downstream sensors. It required a breaker bar, O2 sensor socket, a single spacer (open antifouler) for each bank 1 and 2. Both sensors are fairly close to each other on the exhaust pipes near the oil pain on the passenger side. Breaking the sensors loose in limited space is the hard part. Installed them, cleared my codes, drove for a dozen miles. Got home, no codes, O2 sensors and cat readiness sensors were good.
03-08-18, 02:36 AM
#63
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You pulled both O2 out of the exhaust steam is all. This will turn the light off only. Most states they’re illegal to install & a sniff test on the exhaust will still reveal a problem. I replaced both cats & all 4 sensors before mine was truest fixed.
03-08-18, 10:58 PM
#64
Depending on if you state does visual inspections or just a OBDII plug-in test (like my area), o2 spacers are great to have. For the rear o2 sensor under the passenger side floor, I have had one installed for about a year now with no catalytic codes again. Even if you catalytic converter is still 95% efficient, it can still throw a code so those spacers work amazing. I did install a new gasket originally when I got my GS300 and the code went away but it came back as that gasket failed after about a year.
12-26-19, 02:34 PM
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O2 sensors
it is MOST DEFINITELY your O2 sensors or an exhaust leak, 99.9% of the time its NOT the cats as these cats are built to last forever, it only says CAT because something is causing the CAT to run below its threshold, IE: the sensors or a leak preventing proper air flow. Don't ever listen to anyone if they say its the CAT, I know a few people that got taken for a nice ride by their mechanic because they saw the word CAT and they listened to him and changed the cat, spending over $1,000 and all they had to do was change the O2 sensors. This isnt a cheap american car with cheap cats that can be replaced for $500. These cats are built to last a lifetime, only way they go bad is if they are damaged internally by cracking from an accident or something.
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