Catalytic Converter & O2 Sensors

[White Rock T4R]

Hello All,

Curious about the well documented P0420 error and your success/failure stories. The dealership confirmed it's the catalytic converter (front and rear apparently :ybrick My 2000 SR5 has about 147,000 miles on it and I believe at least one O2 sensor was replaced prior to me buying it a month ago.


Basically, here's what I'm interested to know:

1(a) - If you replaced it, did you go aftermarket or OEM. From what I can tell, it's at least a $1,200 difference in my case.

​

1(b) - It appears that sometimes after the repair, the CEL returns. Anyone want to share success/failure stories on this? I've heard the computer doesn't like the aftermarket cats.

​

2 - Any cases where someone said it was catalytic converter but it was actually O2 sensors instead?​

Thanks for all the help thus far. I wouldn't know anything if it wasn't for this forum.

The dealership confirmed that it's the catalytic converter in my case

 

[atomicbob]

Hello All,

Curious about the well documented P0420 error and your success/failure stories. The dealership confirmed it's the catalytic converter (front and rear apparently :ybrick My 2000 SR5 has about 147,000 miles on it and I believe at least one O2 sensor was replaced prior to me buying it a month ago.


Basically, here's what I'm interested to know:

1(a) - If you replaced it, did you go aftermarket or OEM. From what I can tell, it's at least a $1,200 difference in my case.

​

1(b) - It appears that sometimes after the repair, the CEL returns. Anyone want to share success/failure stories on this? I've heard the computer doesn't like the aftermarket cats.

​

2 - Any cases where someone said it was catalytic converter but it was actually O2 sensors instead?​

Thanks for all the help thus far. I wouldn't know anything if it wasn't for this forum.

The dealership confirmed that it's the catalytic converter in my case

Is the dealer going to fix the problem that caused the cat to fail. Cats do not fail on their own, somethng has to cause the cat to fail. If all you do is replace the cat you will be back in a year to get it replaced again.

My recommendation, check plugs, wires, MAF, upstream/downstream sensors. If you swap sensors, use Denso and swap out both at the same time.

Good info at All Catalytic Converters - Catalytic Converter Failure

 

[99yota4]

Had the p0420 for a while and I just got around to changing the rear O2 sensor because I only had one code. If there were more codes, further troubleshooting would probably suggest the MAF sensor or front o2 sensor. So since I only had the P0420 I diagnosed it to be the rear o2 sensor. Changed it out over the weekend and the cel has not come back yet. I'm hoping that I have solved the issue since the o2 sensor that was replaced looked like it was the original one and it was a pain to remove with the rust.

 

[White Rock T4R]

Thanks for the help guys.

Since I'm new to this 4Runner and not certain what made the cats fail, I'm contemplating whether or not it is financially sensible to spend the money on getting new cats, sensors, etc.

How much is the sensor replacement? Is it something I can do myself. From the board here, it sounds like Denso is the brand to go with.

 

[Nelsonmd]

amazon is the cheapest, they should be about $65 a piece. Check here for the right one for you:
Oxygen / AFR Sensors - Underdog Racing Development

Denso is the only way to go. Don't buy anything else.

This is definitely easy to do, so don't pay anyone to do it for you.

O2 sensors is definitely the place to start, along with checking and cleaning the MAF, plugs, etc...

 

[TheDurk]

I'm not a Search Nazi. But really there are a lot of good threads on this. Just put P0420 in the 'Search this Forum" Box and there is LOTS of good info.

Yes, just about anybody can do it. Get your Denso part number at URD Oxygen / AFR Sensors - Underdog Racing Developmentand buy on Amazon. Get under the truck and look at the sensor. If it's new, there will be nice new nuts on it, or at least ones that are easy to turn. If they are rusted in place, you are a victim of dealer BS--this has happened.

EDIT: Darn you Matt! Got a telephone call while I was typing! (j/k)

 

[White Rock T4R]

Thanks Durk, good stuff.

I'll report back.

 

[ScoobyStew]

I haven't had the opportunity to get a scan done, so i don't know if the P0420 error message is related to me, but I do know that my 2000 4Runner Limited is having some problems with power when trying to accelerate. My wife drives the vehicle the most, and she's had it happen a few times where she goes to accelerate and the vehicle hesitates. She then pushes the pedal a few times and it seems to go away, but during those first few moments it's quite frustrating. Most of the time it seems to have perfectly fine power behind the acclerator, but then out of the blue it just lags. Obviously this isn't a safe condition to be driving with at all. I keep having visions of getting stuck on the railroad tracks or something.

Any help would be greatly appreciated.

 

[Nelsonmd]

Thanks Durk, good stuff.

I'll report back.

No worries, you got the credit...

I haven't had the opportunity to get a scan done, so i don't know if the P0420 error message is related to me, but I do know that my 2000 4Runner Limited is having some problems with power when trying to accelerate. My wife drives the vehicle the most, and she's had it happen a few times where she goes to accelerate and the vehicle hesitates. She then pushes the pedal a few times and it seems to go away, but during those first few moments it's quite frustrating. Most of the time it seems to have perfectly fine power behind the acclerator, but then out of the blue it just lags. Obviously this isn't a safe condition to be driving with at all. I keep having visions of getting stuck on the railroad tracks or something.

Any help would be greatly appreciated.

Uh, that is completely unrelated. Put it in a new thread.

 

[TheDurk]

No worries, you got the credit...



Uh, that is completely unrelated. Put it in a new thread.

Yeah, how about that! Scooby, get the code read before you start the thread, some people don't have a lot of patience with folks who post just about having the light on. (Is your light on? I assume so, or you wouldn't need a scan...) For the record, solo P0420 has ZERO effect on performance (short of a completely plugged cat or something).

 

[PhdNPrerunners]

Here is something you should check. My check engine light was throwing the same code and before I changed the gasket between the cat and the muffler and it fixed the problem. Good luck

 

[Nelsonmd]

Here is something you should check. My check engine light was throwing the same code and before I changed the gasket between the cat and the muffler and it fixed the problem. Good luck

Yeah, an exhaust leak can throw this code too. I have inspected my exhaust from manifold back and saw no sign on leaks, so I don't think that is what is throwing mine.

 

[White Rock T4R]

UPDATE:

After inspecting the O2 sensors, I've determined that the rear O2 sensor seems to be old(er) and probably in need of replacement. The first pic is the one before the cat and the 2nd pic is the one after the cat.

So based on the numerous threads I've read, I think it looks old enough that perhaps it is the O2 sensor instead of the cats (wishful thinking).

So question for the expert panel is: does this O2 sensor look like it needs to be replaced?

If so, is this the Denso you would pick for a V6 2000 2WD 4Runner SR5? 2000*Toyota*4 Runner*Oxygen Sensor from Car Parts Warehouse | Add to Cart

 

[koulee]

Get a multimeter and test it, thats the only way to know for sure.

 

[TheDurk]

The multi-meter test can tell you it is bad, but it can pass that test and still throw a P0420. It does look old enough (considering it's in Texas, that could be one winter old in Massachusetts) that I would change it before I spent money on cats. The link is definitely to the wrong sensors; those are for the 4-cylinder engine. Go here Oxygen / AFR Sensors - Underdog Racing Development to get the right Denso part number, then Google that number and look for the best deal (usually Amazon). Stick with Denso (OEM) sensors.

 

[ryanarcane]

amazon is the cheapest, they should be about $65 a piece. Check here for the right one for you:
Oxygen / AFR Sensors - Underdog Racing Development

Denso is the only way to go. Don't buy anything else.

This is definitely easy to do, so don't pay anyone to do it for you.

O2 sensors is definitely the place to start, along with checking and cleaning the MAF, plugs, etc...

Be careful buying Denso parts from Amazon always check whether it is actually sold by Amazon. There are knock off Denso parts flying around Amazon as Denso at least that's what I learnt. I usually prefer buying it only when the seller is Amazon itself not just a marketplace dealer on Amazon or
RockAuto.com they source their parts directly from Denso.

 

[Bad Luck]

Be careful buying Denso parts from Amazon always check whether it is actually sold by Amazon. There are knock off Denso parts flying around Amazon as Denso at least that's what I learnt. I usually prefer buying it only when the seller is Amazon itself not just a marketplace dealer on Amazon or
RockAuto.com they source their parts directly from Denso.

Congratulations on reviving this beast from the grave! Almost a decade since the last post!arty: