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Old 05-31-2003, 04:03 PM   #1
Cujo31
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Angry P0420 CEL veterans? Stock exhaust/engine. Perm. fix?

Okay, so I lit up a P0420 code this week.... catalyst threshold exceeded on the rear sensor bank1

BONE STOCK 2.5 RS... I think the only thing I changed was I put some 97 octane gas in instead of her usual 87... ????


I did a search and the only answers were for aftermarket mid-pipe/catalytic guys, nothing about stock problems.,,,, many say it comes on every now and then like its normal, they just reset the ECU and get a few 1000 miles till it pops on again...


or is my catalytic conv. just shot? I did run a week or two w/ a bad front O2 sensor about a month ago before I was able to replace it....

anybody out there stock get rid of a P0420 permanently? Thanks guys!!!
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Old 05-31-2003, 09:32 PM   #2
munkis
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how many miles on your car?

the warranty on the cat is 8 years 80,000 miles.

If it keeps comming back sounds like the cat will need to be replaced.

Jay
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Old 05-31-2003, 10:55 PM   #3
HndaTch627
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Quote:
Originally posted by McDade
how many miles on your car?

the warranty on the cat is 8 years 80,000 miles.

If it keeps comming back sounds like the cat will need to be replaced.

Jay
amen brotha!
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Old 06-01-2003, 10:59 AM   #4
Matt
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Thumbs up

I had several problems with this error code. I had a stock exhaust and kept getting this light over the period of a few months. It just came on and off at random regardless of fuel type and driving conditions. My dealer (local at the time in Miami) ordered and replaced the cat. Smelled really bad for a few days, but it disappeared. 19, 000 miles later I have yet to see the light again.
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Old 06-01-2003, 11:20 AM   #5
Cujo31
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awesome... music to my ears. I just reset the CU and we'll see if it comes on again soon.

but yeah I'm nowhere near 80,000 miles so

thanks again!
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Old 06-01-2003, 07:53 PM   #6
m750
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Default Re: P0420 CEL veterans? Stock exhaust/engine. Perm. fix?

Quote:
Originally posted by Cujo31

BONE STOCK 2.5 RS... I think the only thing I changed was I put some 97 octane gas in instead of her usual 87... ????

leaded or unleaded...
if your ran leaded race fuel through your car, your cat is most likely toast.
AO
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Old 06-01-2003, 10:42 PM   #7
Cujo31
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nearest leaded race gas around here is 50 miles away at GIR. ....


unless Citgo is stocking some firewater for the soccer moms around here now...





heh. like I wouldn't know I dumped in race gas jk
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Old 06-02-2003, 04:30 PM   #8
m750
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heh...
People do the stoopidest things, and noting that, there is very little one can assume that someone did, or didn't do.
I believe the CAT's in your RS are covered under warentee.
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Old 06-03-2003, 12:44 PM   #9
Julian
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Also, concerning running with no front O2, this could result in either excessively lean or rich conditions at the cat, either of which could raise the temp of the cat to the point of failure. Did you get a lot of popping during shifts with no O2?
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Old 06-03-2003, 05:36 PM   #10
Cujo31
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well, It was hard to tell if the O2 sensor was completely offline, or if it was actally still doing anything. for example, preiodically the car would drive normally, and then out of nowhere the rpms would drop and I'd have to struggle to keep the car alive by feathering the gas.

there was not really any popping from the exhaust during that period, but the chugging idle and constant feathering at stoplights and between gears on a sluggish-at-best fluctuating voltage from the sensor I know were probably my converter's worst nightmare.

update today is 6/3 and since the original post / reset it hasn't come on again....
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