catalytic converter

I have a 99 Odyssey with 114k miles. At 103k miles the MIL came on
with the codeP0420.I recently had a timing belt service done by a Honda
dealer, they said I needed a new catalytic converter. I have been
driving since 1968 and have favored Hondas. I have never needed a cat.
before and I am starting to lose confidence in Honda's supposed "great"
reliability. Could the cat. really be bad or could it be something
simpler like an oxygen sensor?

 

I'd start by reading the following:
http://www.obd-codes.com/trouble_codes/generic/p0420-catalyst-efficiency-below-threshold-bank-1.php

Then check for the federal warranty on cat converters, etc.
I am not optimistic on the latter, but it's good to know
about it.

Google has a lot of advice on this.

 

Now there's a good link. My own page is on that subject is
looking a bit dated now. I'll replace that soon.

The federal warranty is eight years and 80K miles from date
of original purchase. You can only claim it once.

There are a few California vehicles for which the warranty
is 14 years (not the '99 Odyssey).

 

It could. See Elle's link.

Government emissions requirements these days are stupidly strict. Strict to
the point that some components are operating close to their capability
limits, and failures are common. Ten years ago, your cat would have very
handily met the emissions limits in force at the time.