Need help decoding an error code!!

[AllTheGoodNamesAreGone]

Ok I jsut got auto tap.. and Love it!
However my car keeps triggering the code

P0420
according to auto taps website meens

TWC System Low Efficiency Bank 1
I dont understand what that means

Now.. I belive that code description in auto tap was a little diffrent, and I was told earlyer that I had a bad O2 sensor..

Anyone care to tell me if this is in fact correct? that and which sensor is the (bank/#) 1 sensor?

Thanks in advance for all the help..

~Billy :cool:

[Dan90RS]

Three way catalyst low efficiency. 99% of the time it means your catalytic converter is bad. Even worse, aftermarket cats are known to be below OBDII standards so you have to get a factory cat ($$$) or something like an O2 sim.

If you have low mileage you may be in luck. Catalytic converters are covered under emissions warranty for either 7yrs/70,000 miles OR 8yrs/80,000 miles depending on where you live. You might be able to get a free cat.

Oh yeah, "Bank 1" is determined by the #1 cylinder. If you have a 3.8, Bank 1 is on the driver side.

[ February 01, 2003: Message edited by: Dan90RS ]</p>

[AllTheGoodNamesAreGone]

Hmm interesting responce..

I do have an aftermarket 3" catco cat..

Here is the full story.. I know about the extended warentee on the cat..
BUT i didnt know about it tall after
I said screw the 1100 GM cat..
The dealer I took it to was trying to blame
it on the cold air modual ruined the cat.. But I have had exhaust problems since I first got the car.. Its a big load of [img]graemlins/bs.gif[/img]

So currently I have the 3" catco followed by the edelbrock catback exhaust.. any my original O2 sensors.. the car has under 36K...

The problem first occured when i was driving in the snow.. So i took it to a local shop that I have been working with for like 10 years.. (i know the owner).. anyway they cleared the code.. and checked the lines on the O2 sensors.. everythink looked ok.. Like it was a fluke..

So I was like Ok.. no problem.. then about a week or two later the light came on again (i was driving in the snow again) so i decided to jsut get auto tap assuming that the cold was causing the problem and i figured I would jsut clear the code when it came up..

I cleared the code today! and it was cool for a while.. then it came up again (after about 30-40 mins of driving) today the roads were not too wet.. no snow.. but its cold below 40 degs...

So.. What would be the recomended course of action?? Any one have a suggestion.. I dont want the crappy GM cat.. in fact.. i am really sick of dealing with them in general..

So, new O2 sensor or sims seem to be my options.. whats the best option? whats a good place to get them?

Thanks again,
Billy

I dont really want to waste my time with the dealership..

[AllTheGoodNamesAreGone]

Ok, acctualy I think I have a better understanding of the problem now.. I read a little in the haynes manual I have..

So i have 3 o2 sensors.. one on each manifold, and one after the cat..

So why would only the bank 1 sensor go off? if the cat was not working efficently?

that and my other questions above still apply.
so any answers to them would be helpfull also..

That and i think it may be due to the fact that its cold out.. because if the cat were not getting hot enough then maybe its not working as well as it shuld..

So i was thinking that maybe a 2.25 or 2.5 inch cat would be a better option?

any advice / experence would be helpfull..

~Billy

[Go4broke]

I am in the same boat as you I too have the P420 code and it won't go away I took mine up to the shop that installed my exhaust and they found a leek and fix it then a day later the code came back on again the last thing I did to the exhaust is put headers on and that was like 2 months ago no problem till now. When I get some money I will try new O2 sensors and see if that works. you can get OEM ones for $60 at AutoZone and Bosh O2 sensors for $65.

[AllTheGoodNamesAreGone]

Hmm.. Yeah and this boat sucks..

I reset the code again.. and it has not come back today.. today it was warmer.. almost 50..

I like my heat theory, and i think i am going to wait a month to see how things turn out as it warms up.. However I may make a trip to advanced auto parts and pick up some O2 sensors..

let me know if you have any luck with the o2 sensors.. Kain4567@aol.com

How do most people deal with this?

~Billy