01 Toyota Corolla with Cat eff code

jay

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#1
112,000 miles, auto, 1.8l.
Has P0420 Cat eff code.
Owner reports Cat was replace once under warranty.
Graphed post Cat O2 sensor activity and saw it very active, close to same activity as Sensor 1.
No other codes or problems found. Fuel trims look good.

I'm going to send them to someone for new Cat.
Are there any aftermarket Cats that can be used without problems. If so, what manufacturers?

Thanks, jay
 

Transman

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#2
How is the upstream o2 working? Is it moving fast and full range? The cat efficiency code is simple math, it compares the front o2 with the rear o2 only. This may have nothing to do with how the cat is actually working. The most common cause of a cat code is the front o2 failing. Post back, Transman
 

jay

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#3
Front O2 has good sweep from rich to lean; crross counts good.
 

jjm

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#4
If the rear behind cat O2 sensor is reading all over the place, chances are indeed the cat is bad. The rear behind cat O2 sensor output should be fairly smooth and stable on a properly functioning cat.

I've seen a disproportionate number of cat failures on Honda and especially on Toyota, so it wouldn't surprise me if this was the second one for this vehicle in 118,000 miles. I suspect manufacturers have been "pushing" cats in an effort to make their vehicles greener to the detriment of cat life. But heck, when you're saving the planet what's a couple of dollars of out the family budget?

ABSOLUTELY FORGET AFTERMARKET ANYTHING, especially a cat. I just went through HELL with an aftermarket cat for the wife's '01 Camry hoping to save money, but it ended up costing me a hell of a lot more. I'll spare you the gory details - unless you're interested. I realize the cat on this vehicle lists for over $1,100, but to save your sanity, just bite the bullet and go OEM, right down to the bolts and seals.

Joe

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jay

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#5
I hate to hear about the problem with aftermarket cats. In tech school, we replaced a few with aftermarket from local parts stores without any problem. They were used on Ford/GM/Chry cars; perhaps the Hondas/toys are more sensitive to cats.
I know it is important that the spacing from the rear of cat to rear 02 sensor be measured and the new installed at same distance or MIL light (P0420) will come one. I heard this tip from a guy in muffler shop business. Thanks for the info. jay