Re: "Catalyst efficiency" code -- questions

From: Bernd D. Ratsch (fasstdak@hotmail.com)
Date: Sat Feb 28 2004 - 14:29:51 EST


With any aftermarket High-Flow cat, the factory specs are changed and the
rear O2 (which monitors Cat efficiency) will see different parameters -
causing the code. Just install either an O2-SIMM or KatBox and you'll be
done.

- Bernd

----- Original Message -----
From: "Grady Ogburn" <jgo@nospamplease.uswest.net>
To: <dakota-truck-moderator@bent.twistedbits.net>
Sent: Saturday, February 28, 2004 1:08 PM
Subject: DML: "Catalyst efficiency" code -- questions

>
> Folks-
>
> My Dak threw a MIL light. I used OBD-2 on my laptop to pull the
> code: "P0420 - Catalyst efficiency below required level".
>
> I've put just under 40k easy miles on the truck. Aside from the
> sensor, which is original, the entire exhaust is aftermarket
> with about 25k on it. The CAT is a 3" high flow unit.
>
> I have no other reason to believe that the cat really is bad,
> although I have developed a new "clunk" directly under the cab
> that I hear when I'm cornering on bumpy roads, that I think is
> unrelated. Bad CATs sound like a can full of marbles/gravel,
> right?
>
> I have a coupla quick questions.
>
> 1. Is it presumptuous to suspect the sensor rather than the CAT?
> 2. Is that code conclusive evidence that the rear O2 sensor is
> out-of-whack?
> 3. Can the O2 sensor be cleaned, or must it be replaced? TonyC
> (FAQ) believes you can use carb cleaner -- does anyone disagree?
> 4. Any special tools to swap an O2 sensor?
> 5. Does Bosch make the the best replacement part?
>
> Thanks,
> Grady
>



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