It's possible there can be a problem in the wires for the diagnostic
plug that would prevent clearing codes, but I'd say it's very unlikely.
I've seen this problem that was only cured by a new ECU, but that was on
a 10 valve model with the Siemens system. Most often when someone can't
clear a code, it's because they haven't just read it. The sequence has
to be: Ignition on, read all codes, clear all codes. If you've turned
the ignition off after reading the codes, then they won't clear. And of
course there's always the "disconnect the battery for a while" method,
just make sure you have your radio code.
For your EGR flow fault code, try taking the EGR valve off the intake
manifold and cleaning it.
http://www.volvospeed.com/Repair/egr.php
--
Mike F.
Thornhill (near Toronto), Ont.
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)
