Hey there Guest!
Hey - did you know if you click on the title of a thread it will take you to the first unread post since you last visited that thread?
but were afraid to ask: 
STOP!! Never post your email address in open forums. Bots can "harvest" your email! If you must share your email use a Private Message or use the 
smilie in place of the real @
Pretty Please - add it to our Events forum(s) and add to the calendar! >> 
Offline
I have a Chevy Astro Van that I use to haul bulky or heavy things and to pull a trailer. It usually goes less than 1000 miles a year and for the past couple of years most of that was doing drive cycles in an attempt to get the I/M "ready". It sits for long periods particularly in the winter and if the battery gets low the readiness needs to reset. In the past it has reset after a few hundred miles, some of which was the recommended "drive cycle protocol". It was always the CAT monitor.
This year the CAT did not clear after 500 miles. No codes, stored or otherwise, and no CE light ever. My local inspection station could only recommend keep driving. In desperation I went to the Chevy dealer and they cleared it the same day.
It seems that the problem was a loose plug-in connection on the alternator. I'm no EE and I can't get my head around that at all. If a voltage spike, why only the CAT? I did replace the alternator a couple of years ago, so I am responsible for the loose plug but the issue was going on before that, although it would clear after a couple of hundred miles before this year.
Problem solved for now but I am completely baffled as to what went on.
Any ideas, wisecracks, jokes or theories will be appreciated.
Tom
This year the CAT did not clear after 500 miles. No codes, stored or otherwise, and no CE light ever. My local inspection station could only recommend keep driving. In desperation I went to the Chevy dealer and they cleared it the same day.
It seems that the problem was a loose plug-in connection on the alternator. I'm no EE and I can't get my head around that at all. If a voltage spike, why only the CAT? I did replace the alternator a couple of years ago, so I am responsible for the loose plug but the issue was going on before that, although it would clear after a couple of hundred miles before this year.
Problem solved for now but I am completely baffled as to what went on.
Any ideas, wisecracks, jokes or theories will be appreciated.
Tom
A friendly reminder - be careful what links you click on here. If a link is posted by someone you don't know, or the URL looks fishy, DON'T CLICK. Spammers sometimes post links that lead to sites that can infect your computer, so be mindful what you click.