[AT] Tractor hauler question.

[Stephen Offiler]

On Tue, Aug 26, 2008 at 9:10 AM, Don  Bowen <don.bowen at earthlink.net> wrote:

> I California you cannot pass if any of the IM codes are not set.  The check
> engine light may be out but the tester reads the IM codes because they are
> afraid you may have cleared the codes.

Right, Don.  Those are called "monitors".  Monitors are software
routines in the computer that do specific checks for fault conditions.
 Some monitors only run when a number of conditions have been met (air
temp of such-and-such, engine temp of such-and-such, "x" time at "y"
MPH, and so on).  If you have problems with your car and just unhook
the battery to clear codes right before you pull up to the inspection
station, you will have a large number of monitors that have not had a
chance to run.  Thus, for a successful emissions inspection, ALL
monitors must have been run, and ALL must be successful.  (There are a
couple minor exceptions to this in some states but that's the jist of
it)

Steve O.