cat converter o2 help 00 runner (1 Viewer)

[flykrs1]

00 4Runner. My check engine light has been going on and off over the last few weeks. I determined it was the dreaded p0420 code. It went off before I could get it to Toyota (still under Fed Emissions warranty). My truck has TRD headers (welded to cats for some reason) and Cat Back. The light finally came on again this weekend and I took the rig into Toyota Monday. They found the problem to be a cat. Then they accused me of replacing the stock cat with an aftermarket because they did not recognize it. I told them to check their facts again. So this morning they determined the cat to be a Toyota brand and also told me that both O2 sensors need replacing for $800ish. From what I have read I am not sure they can determine if the O2 sensors are bad until the cat is replaced.

Any help is greatly appreciated, thanks.

 

[silversup]

I am not very familar with 00 4runners. But I would be imagine that if the O2 sensors are bad, they would be throwing a code. You should get it scanned. Did they change the placement of the the cats/O2 sensor when they welded the headers to the cats?

 

[danstoyshop]

Help is on the way!!!

Our shop has done numerous convertor replacements with aftermarket parts. We have only have had one problem to date and it was this particular application. Overkill appears to be the answer. Rather than install the obvious large, free-flowing convertor we were forced to install 2 convertors in tandem as close to the Y-pipe as possible. It is also very unlikely that it needs the O2 sensors replaced, but they do seize in the pipes in easily. The dealer is probably pulling a CYA. Remember that the cat doesn't actually have to be bad to set the code, it just has to be below a certain efficiency threshold.

The only other thing to consider is that cheap convertors don't perform well and could run cool enough the same code sets again anyway. Good luck.

 

[SteveH]

I get this 420 code every 6 mo. - 1 year on on my '95 FZJ80. There are no obvious leaks of any sort and gas mileage is as good as ever. Rather than go down the road of non-Toyota cats and oxygen sensor replacement, I turn out the light every time it comes on (infrequently) with a code-dumper/resetter tool and don't worry about it. This may not be practical for you, but it's free.

A good tech should be able to watch the O2 sensor output from each sensor and see if it looks like it should, rather than just throw your money at it until the light goes out. He could monitor the output through a warmup cycle to see if the catalyst reaches a certain level of efficiency. But, this may be far beyond what the dealership manager wants/allows/lets him do.

Steve

 

[Jukelemon]

As SteveH has stated, every dealer should be able to run an O2 sensor analysis to see if the readings are abnormal and/or indicate a cat or sensor failure.

From my experience, the Toyota cats are pretty robust and last a long time e.g. my truck has the original cat, 170k and tests fine.