Bob,
I went and got my little book, which your local Auto Zone store should have
done, that list's the all the generic codes, their meaning and probable
causes for the code. P0420, according to the book I have, says:
P0420 thru P0422
Catalyst efficiency low bank one
The oxygen sensors monitor the catalytic converters ability to store oxygen.
Probable causes
1st. Catalytic converter defective (Failure possibly due to #2,3,or 4)
2nd Engine misfire or running condition
3rd Large vacuum leak
4th Engine oil leakage into exhaust-valve guide seals, piston rings
Either way you go, it would seem you have a bad cat. How many miles do you
have on the truck? I forget what the limit is but the manufacture has to
warranty the cat as part of the emission system for, I think, 80K miles and
6 years. IF you are under the mileage, you may be able to get it replaced at
the dealer for free. I had mine done a couple of years ago when I heard
something rattling in the cat when the truck had over 50K miles on it. You
also need to look at the other items on that list and see if any of them
apply to your truck. Since you don't mention you had a code pulled for a
misfire, (they would be P0300, random multiple misfires, P0301, misfire #1
cylinder, etc.) A misfire doesn't seem likely. A vacuum leak should be easy
enough to recognize. I found a troubleshooting guide that gave an easy way
to find vacuum leaks. With the engine running, take a propane plumbers torch
and open the valve but do not light the torch. Aim the nozzle around the
hoses and intake manifold, wherever you suspect a vacuum leak. When the
engine RPM picks up, you have probably found the leak. Engine oil leakage
should also be easy to rule out if you keep a close eye on you oil
consumption.
Let us know how this turns out for you and what your solution is.
HTH,
Ray Irons,
Dover, DE
-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net]On Behalf Of bob
Sent: Sunday, February 20, 2005 4:21 PM
To: dakota-truck-moderator@bent.twistedbits.net
Subject: DML: Trouble code P0420
After getting a "CHECK ENGINE LIGHT" I went to Auto Zone and had the
code pulled. They said it was a P0420. The print out gave the following:
The PCM has determined that the catalyst system efficiency for Bank 1 is
below threshold for the current engine operating conditions. (Bank 1
identifies the location of cylinder #1, while Bank 2 identifies the
cylinder of the opposite Bank). They were not very helpful in
identifying possible solutions. Any ideas? Thanks
Bob
99 Dakota
This archive was generated by hypermail 2b29 : Tue Mar 01 2005 - 10:04:31 EST