Malfunction Indicator Light..
aka
CEL ..Check Engine Light.

does your system have or use a CEL ?
it's nice to have.
on some systems....earlier ones, you read codes by counting flashes of the
CEL when you put the system in the right mode for that.
On OBD-II systems..which always have a CEL ..
you plug into the diagnostic tester with your code reader or software ..
and see what the codes are.
OBD-II codes are far more sophisticated than OBD-I ones.   Considerable so.

Haynes OBD-II manual is great reading.
Scott
www.turbovans.com
----- Original Message -----
From: "Don Hanson" <dhanson928@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, August 25, 2011 10:29 PM
Subject: Re: Van Died @ 70 MPH. Why? (Jetta conversion)

>  OK, this is dumb but have you checked your Temp II sensor?  When I hear
> very low idle and hunting around at start up, and put that with hot
> weather
> problems...Check that thing....
>  Don Hanson
>
>  What is an MIL?  Is it crucial to the vehicle, does it do something
> important?  Do I have one?  Should I get one?