LS1NyteMare

I was cruising around 30mph monday and my SES light comes on, I don't think it is too big of a deal because i don't hear any strange noises and there is no change in performance. Any ideas on what could be setting it off? It a 1998 TA A4 with 59xxx miles. Thanks

Nightrydass

You need to scan the PCM

LS1NyteMare

how do i do that lol I'm dumb

406malibu

autozone

LS1NyteMare

thanks, i will get that done today

LS1NyteMare

i finally got my pcm scanned at autozone and this is what is said, low efficiency catalytic converter bank 2, it said this could be due to either a bad cat, a vacum leak, and oil spill into the exhaust, or a O2 that needs replacing. I am leaning toward the O2 sensor because i do not hear any new noises nor do i smell any odors. Am i correct in this judgment? Also my SES light has been on since the first post but suddenly tonight it went of and then after about two hours it came back on. What could be causing this?

Camaro2iDie

iTrader: (1)

Do you notice decrease in performance? 9/10 it's most likely your cat. It's pretty unlikely for 02 sensors to go out.

Camaro2iDie

iTrader: (1)

what was the code? P0421?

2001NBMZ28

Sounds like a bad passenger side cat, code was probably P0430. Have the code checked again to be sure it's not something else since the light went off then on again. You can check the post cat 02, exhaust for leaks, etc. but it's usually the cat. www.gearchatter.com/viewtopic8708.php

ophee

iTrader: (5)

I had this problem about a month ago. Same code and everything. It was bs... i haven't reset the CHANGE OIL light for about 5 or so oil changes... i threw the light on and it freaked me out for a while. So i changed my oil, and finally reset the counter.. and the light never turned back on. Hope that's your case...

98Bird

I don't think that's the same thing. You need a scanner to check what the code is. The change oil/maintenance light is not that. I didn't even know Fbodies had one (maybe in later years?).

The code he's having can go off on their own or cleared with a scanner and not come back right away or for a long time, b/c it would depend on how bad the cat was clogged. The clogging could be minor and maybe the small obstruction was expelled.

ghardester

Do you have any recently new rattles coming from under the car? If yes, you probably have a bad CAT.

DVS99TRANS

iTrader: (7)

GM sent out a TSB (technical service bulliten) on 01 and 02 LS1 fbodys about coming out of the factory with bad cats. Emissions are covered for 10 year/100,000 miles if it isn't modded at all. I would think it would be a o2 though. O2s are supposed to be changed out like sparkplugs, just no one does it.

LS1NyteMare

the code was P0430 what does that mean

DVS99TRANS

iTrader: (7)

This might help a little.
http://www.obd-codes.com/p0430
I would start by swapping the rear o2 sensors or buy a new one and try it. If the code changes after switching them to the other side then bad o2, or light doesn't disappear afterwards with the new one=Bad cat. Since the light is intermittent, it will most likely be a bad o2.