Check Engine Light - code p0420 - Catalytic Converter replacement

[Robhu]

An after market cat has to meet the same minimum federal or state standards as an OEM.
Go to a good local muffler shop thats been in business for years and has an honest reputation. (preferrably not a national chain, they make money by ripping you off).
In my area there is a locally owned muffler shop that replaced mine for less than $150.00 total for parts and labor. My vehicle then passed inspection/e-check with flying colors.
I don't do dealers and I don't do national chains. I take my stuff to locals who don't try to make retirement off of one customer.
But you have to shop around, ask around. The best references are word of mouth from satisfied customers. And that usualy comes from customers who know the good independent shops.

[jaydez]

p0420 is a generic fault code and not necessarily a bad cat. I would try cleaning the MAF first. When was the last time the spark plugs were changed? If they are fouled out it will cause this code. I would also suspect the upstream O2 sensor. Oil or coolant leaking into the combustion chamber will also cause this code.

The code is generated when the catalyst in the converter is not able to properly clean what is coming through it. A converter is designed to last over 150k miles and if it goes bad before then there is a problem before the cat.

If your mechanic sees this code he should know better and try to find the cause of the problem. If you let him replace the cat he will make a lot of money off you and you will be back in a year or 2 with the same problem and the new cat will all of a sudden be "bad" too.

do a Google search of "p0420 1998 corolla" and see what comes up. most of the posts are for 2001 corollas but I dont think the car changed much in those 3 years.

[thumper477]

The PO420 code is generated by the computer comparing the readings from the oxygen sensor before the converter to the sensor after the converter.A perfectly good cat will show a code if there is ANY exhaust leak,no matter how small,between the two sensor locations.I have fixed many cars and trucks with this code just by repairing small exhaust leaks.Any leaks behind the rear sensor don't count.Sometimes it's just a cheap clamp or flange gasket replacement for under 50 bucks to get the light to go out.

[LosingBattle]

You can disconnect your battery or maybe have to pull a fuse for a few seconds and you'll reset the check engine light. If you want, drive around some more and see if it comes back on with the same code.

1 second google search brought up a list of catalytic convertors for your car

Car Part Wholesale - Auto Parts and Accessories Catalog - Catalytic Converter For 1998 Toyota Corolla LE 4 Cyl 1.8L

Prices ranging from $75 on up. Some only 49 state legal, some 50 state legal, choose accordingly.

It's a very easy fix. If you can change a tire, you can change this. The hardest part is just trying to get the bolts off without stripping them or bloodying your knuckles.

If you order it from the link here, make sure it's actually correct for what you need.

[harald]

ive actually had some luck passing the emission control ,by tearing out the stuff inside the catalysator on some cars.they obviously isn`t that effective.
the most important is to have a clean airfilter and sparkplugs.

[bjh]

Originally Posted by RTFI

...The line the mechanic is giving is BS....

Originally Posted by thumper477

The PO420 code is generated by the computer comparing the readings from the oxygen sensor before the converter to the sensor after the converter.A perfectly good cat will show a code if there is ANY exhaust leak,no matter how small,between the two sensor locations.I have fixed many cars and trucks with this code just by repairing small exhaust leaks.Any leaks behind the rear sensor don't count.Sometimes it's just a cheap clamp or flange gasket replacement for under 50 bucks to get the light to go out.

Sometimes it is the gas cap! Heck of a lot less than a catalytic converter.