Replace cat converters or O2 sensors? Warranty issue or not? Also need pics pls.

atomic punk

atomic punk

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http://www.toyota-4runner.org/4th-gen-t4rs/96565-pics-writeup-replacing-o2-sensors.html

Quick update: dealer ran the diagnosis and said that 2 catalytic converters need to be replaced. $2400. I'm seriously considering replacing the rear O2 sensors myself first and see if that clears the CEL code (P0420/P0430). The symptoms are slightly erratic idle and maaaybe a bit of a hesitation - tough to tell really. The gas mileage is normal.

I was fighting with Toyota warranty coverage trying to get the to pay for this repair since it happened about 200miles after the warranty is up... until I found out that the cats are only covered up to 80k miles, not 100k. Dealer says that the "Freeze Frame" data cannot accurately show you the mileage of 'when' the CEL light first came on: warranty guys said it can. I'm confused there.

Gotta love the manufacturer's concept of "planned obselecence"
 
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Cats go and take out O2 sensors but lots of things can cause an O2 sensor to go bad. Running rich, fouled plugs, ect. I'd replace the O2 sensors first since if the cats ARE bad they're probably toast anyway. Man, $2400 for cats is STEEP! I thought VWs were $$$. A decent shop should be able to hook up a diag and see the specs at the O2 sensor before the cat and then compare it to the O2 sensor after the cat and go from there. Have it looked at by a decent shop (and not just the dealer) before throwing $$$ at it for sure. Good luck.
 
Odd.

FYI, a hesitation or sluggishness can be a sign of a clogged/failed cat. If the cat has become fouled or plugged, for whatever reason (and there are several) the Cat will start to clog up. As this occurs, you will get more back pressure on the engine which in turn will show up as a hesitation...


and it will pop a code, as the o2 sensor will show the exhaust is not what it should.
 
Thanks for the replies guys. I'm not sure there is a hesitation in acceleration, I probably misspoke/typed: it's more like a hesitation or erratic idle.

I have 2 OEM Denso rear O2 sensors on order from Autozone that I'll install this week. Disconnect the battery, run it for a while, see if the CEL still comes on... then go to a local shop for a cat replacement if the code comes up again. I'm reading that mid-grade and OEM cats are the ones to get, not the cheap ones.
 
I just had my cats replaced under warranty--service writer said it would have been $4800 in another 6Kmiles (I have 74K on my '05 now)
 
To make this whole situation even more troublesome, I even had the cat(s) replaced already under the famous "sulfer TSB" about 40k miles ago. But even the new cat(s) are out of warranty.
 
I just got back from the dealer this evening and they are replacing the cats under the sulfer TSB. I have 75,500 miles.............
 
dan18932 said:
I just got back from the dealer this evening and they are replacing the cats under the sulfer TSB. I have 75,500 miles.............
Click to expand...

You're lucky... hindsight - I should've waited until I was close to the end of the warranty (80k miles) to get that TSB done. I got it done at 20k.
 
MANY MANY times cats are replaced when the actual problem is just an O2 sensor. Bad O2 sensors can give a faulty reading. A GOOD mechanic will do more tests to determine exactly what the problem is (Cat or just bad O2 sensor).

I've driven well over 1 million miles on several vehicles since Catalytic converts became mandatory on vehicles and I've only ONCE ever had to replace one..and that was due to a rock hitting it and destroying it.

If you're mechanically inclined then get a shop manual and there at specific tests you can run to determine if it's the catalytic converter of the O2 sensor. If you don't have access to those tests...then just replace the O2 sensor. Then clear the code and see if the code comes back.

Personally I only use Autozone for things like Wax or oil...I've had bad luck with some of the crap parts they sell. You can buy NGK O2 sensors on-line. NGK makes excellent sensors...Not sure what brand Autozone sells.

There are GOOD aftermarket Catalytic converters also. Just buy one that's a direct replacement for you vehicle...Not a generic one that fits ALL vehicles. Even the good ones less then half the price of an OEM cat.
 
MikeInNH said:
MANY MANY times cats are replaced when the actual problem is just an O2 sensor. Bad O2 sensors can give a faulty reading. A GOOD mechanic will do more tests to determine exactly what the problem is (Cat or just bad O2 sensor).

I've driven well over 1 million miles on several vehicles since Catalytic converts became mandatory on vehicles and I've only ONCE ever had to replace one..and that was due to a rock hitting it and destroying it.

If you're mechanically inclined then get a shop manual and there at specific tests you can run to determine if it's the catalytic converter of the O2 sensor. If you don't have access to those tests...then just replace the O2 sensor. Then clear the code and see if the code comes back.

Personally I only use Autozone for things like Wax or oil...I've had bad luck with some of the crap parts they sell. You can buy NGK O2 sensors on-line. NGK makes excellent sensors...Not sure what brand Autozone sells.

There are GOOD aftermarket Catalytic converters also. Just buy one that's a direct replacement for you vehicle...Not a generic one that fits ALL vehicles. Even the good ones less then half the price of an OEM cat.
Click to expand...

unfortunately, if you have a 4th gen v8 runner, the cat is part of the exhaust manifold, which has zero aftermarket you have to get from the stealership.
I was quoted $2000 taxes in to replace one of mine.
 
unfortunately, if you have a 4th gen v8 runner, the cat is part of the exhaust manifold, which has zero aftermarket you have to get from the stealership.
I was quoted $2000 taxes in to replace one of mine.
Click to expand...

That's very unfortunate....Subaru started this design back in the 70's. I thought it was dumb then and still do today. There is no reason it has to be an integrated design with the exhaust manifold.
 
Eastcoastrunner said:
i can think of one reason Toyota did so... $$$$$$
Click to expand...
Toyota can think of 2000 reasons they did so.

I thought you could buy an aftermarket direct-replacement cat for the 4th gen? How come all the parts websites - Autozone, NAPA, etc - show OEM replacements (& universals) ?

My two O2 rear sensors will be R&R'd this weekend.

In the meantime - does anyone know where there is a good writeup on how to do it?? I haven't found anything, including pics, even in the Tacoma forums. I could have missed one, but with such a common problem, I expected many writeups.

Lastly, I have the full diagnostic "Freeze Frame" data results. Which line items would tell me that a cat is bad? I don't even know what the "-3,-2,-1,0,1" column headers mean.... but there is a line that shows my O2S B2S2 increasing under those columns from .09,.13,.27,.19,.41
The only other O2S that I see remains relatively constant around .52-.72
 
Just got a call from the dealer after dropping it off this am. They replaced both cats and both oxygen sensors! I pretty much have new exhaust now. When I pick it up I will post the tsb #
 
The rear cat outputs should stay around .5 volt and not move and the front ones will move from low to high and switch back and forth.
 
Damn I wish I would have had the cats replaced due to the sulfur smell TSB. I'm just over 80k, I wonder if they would consider doing it still? probably no.
 
Ok got the car back and the tsb is 0346-09. Total came out to be 2250. Glad I had this done before the warranty was up :)
 
FireTruckGuy said:
The rear cat outputs should stay around .5 volt and not move and the front ones will move from low to high and switch back and forth.
Click to expand...

You mean the rear O2 sensor outputs, right? Just making sure. Any idea if there are any web writeup/pics? I'm going to be doing the R&R totally blind if I can't find any.
 
dan18932 said:
Ok got the car back and the tsb is 0346-09. Total came out to be 2250. Glad I had this done before the warranty was up :)
Click to expand...

That's certainly good news for you... but don't rest TOO easy. I had the TSB done at 20k miles and 1 of the cats replaced. So if indeed my problem right now is 2 bad cats, then that means the replaced one went bad right at 80k miles. Planned obsolescence.
 
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