[s-cars] (no subject)

[JC]

>
> I would operate under the assumption that the ECU can somehow
> sense when the computer is plugged in/powered up.
>

I sometimes have a similar situation with my setup - a cheapo online
purchased 2x2 adapter used with an 'obsolete' official VAG-COM serial port
adapter (forget the model number now... but requires running the ancient old
software)

When the cables and PC are hooked up but VAG-COM is not yet running and
scanning the interface it sometimes seems to trigger the engine light. But
not because of a code I think, only because of some interface behavior that
lights the light when a cable is connected but a scanner has not yet
negotiated a connection with the system. Once the VAG-COM is running and
pulling codes all is normal and light goes off.  At first it alarmed me and
I'd do extra 'code clearing' to be sure all was well but now I just boot the
computer first before turning the ignition on...

HTH - not sure if it's the same but FWIW...