P0420 & P0430 Codes, When will it end???

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a77boy

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P0420 & P0430 Codes, When will it end???

I know that this topic has been beat to death with these two pain in the A$$ codes, but I was hoping for a little more insight. My 2003 4 runner V8 keeps throwing the same two codes, P0420 & P0430. I can disconnect the battery and the CEL will stay off for a few days but always comes back on. After much reading on the Forums I took it to the Dealership to try and verify a few things. Service writer did verify that it was the bank 1 and bank 2 sensors. BUT what he couldn
 
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If I was guessing between these two, I'd be much more confident going with the sensors beig the culprit.
 
toybox said:
If I was guessing between these two, I'd be much more confident going with the sensors beig the culprit.
Click to expand...

But those codes mean it could be either of the 2 sensors or the cat. Weird that it would also trigger codes for both sides at the same time.
Not sure the proper diagnosis but would it help to get a cheap e-test to rule out the cats (was a test done recently due to the sale?) You should pass the sniffer test if the cats are OK.
 
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Hey guys, THANKS for your input. I took the 4 runner to a really reliable mechanic (in my opinion at least) and he was able to actually check the voltages thoroughly on the O2 sensors using his diagnostic scanner. I was even able to graph them. Seems that the voltage on them was fluctuating quite a bit and the waveforms were all screwed up. Definitely going to replace those first. I know it is odd that they seem to both be malfunctioning but after resetting the codes seems that only one of them showed up P0430, but it all seems so much cheaper than trying to replace the CAT's. Thanks again.
 
a77boy said:
Hey guys, THANKS for your input. I took the 4 runner to a really reliable mechanic (in my opinion at least) and he was able to actually check the voltages thoroughly on the O2 sensors using his diagnostic scanner. I was even able to graph them. Seems that the voltage on them was fluctuating quite a bit and the waveforms were all screwed up. Definitely going to replace those first. I know it is odd that they seem to both be malfunctioning but after resetting the codes seems that only one of them showed up P0430, but it all seems so much cheaper than trying to replace the CAT's. Thanks again.
Click to expand...

If it is considered part of the emission control system then it should be under warranty for something like 60k miles. At least that's the way it works here in Califunky ...... oops .... California. By law here in the state of CA a mfgr has to repair a faulty emission system component based on mileage and not years.
 
Emissions warranty is till 80k and it is federally mandated.

Had my catalytic converter and a bunch of other emissions stuff replaced 6 months ago. My mileage was 79,983. Boy was I really lucky. $2,800 lucky.
 
It is very rare for a Cat to go bad at that mileage, unless it has been poisoned by running rich for a long time. The oxygen sensors are not a reliable part. They go bad often on many vehicles. They can drift as well.
 
I put one on my Jeep at 190,000 miles to pass inspection.
My Corolla lasted 155,000.
My Volvo is still original with 163,000 miles.

My experience with O2 sensors is that they need replacement sometime around 90,000 miles. Some go much sooner and some last longer.
 
yeah, looks like the 4Runner cat is almost a solid piece with the exhaust header. Pretty sure its just the dam 02 sensor. Thanks
 
as long as the engine remains in fair running condition a catalytic convertor should never have to be replaced. they are designed to last the lifetime of the vehicle....at least, in theory.
 
If my cat were to ever crap out I would just install an 02 sensor eliminator. Dam cats are way to pricey! Plus in Texas we don't have to pass an emissions test
 
p0430

Have the same situation on my 03 V6 T4R. CEL, VSC TRAC & TRAC OFF lights went on the same time. Scanner pulled out a P0430 DTC. Dis search this forum for the solution but no luck. Anybody had this solved? What is the common problem? Gas cap is tight. Appreciate any recommendations.
 
P0420 and P0430

I have these codes too. How do I fix it ?

How do I know my sensors are good or bad? (AF and O2)

I have 196k on the clock. I think my Cat converter is bad.

any other opinions?

Thanks
 
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