WHY did you reset it? Your only hope now is it comes back before the 80k. A
letter will mean nothing to Honda. Chances are the dealer would have reset
it also but you would then have proof it failed before 80k.
Since you are playing with an OBDII tester compare the front and back O2
sensors and see if catalyst is not working. Also see if the non-continuous
run cycles are complete. It could take a week for some to complete depending
on your driving habits. They all got reset when you reset the code. The
catalyst efficiency test has to be complete before the code will be set....


"MAT" <marcoat*RM_@SPAM_*hotmail.com> wrote in message
news:aP-dnfpSA9sjmrbeRVn-hw@comcast.com...
> My 2002 Civic Si threw a MIL, P0420 (catalytic converter operating under
> efficiency threshhold). I'm now very concerned because of the 80k/8 year
> catalyst warranty of which my car is now at 79.4K miles!. I cleared the
> code and it has not come back in ~100 miles. Now I intend to do the
> diagnostic test in the FSM. It entails start the car, hold at 3000 rpm
> until radiator fan comes on, then drive 30 seconds in 4th gear between
> 55-62 mph, and close the throttle for 1-2 seconds and repeat 4 times. I
> plan on doing this procedure late tonight or tomorrow night when I can do
> this somewhat peculiar maneuver. My concern is that it looks like it
> would be easy to get a false negative. Does the step where I hold rpms at
> 3k trigger some diagnostic mode or is it to ensure a properly warmed
> engine? Could I do this on the way home from somewhere at operating temp
> or does the ommision of the 3k step nullify the result? Should I bother
> sending a dealer or Honda a letter stating what happened in case it comes
> back after 80k, will it help with a good faith repair? The procedure is
> supposed to either trip the MIL again indicating a bad TWC or if not, to
> be considered an intermittent failure where the code is cleared and life
> goes on. I am hoping for the latter or a replacement before 80k, thanks!
>
>