andy I tried all your suggestions
the car is a 93 audi 100cs with a v6 engine
I am able to connect to the tranny and AC
but not to the engine..
I am using the old ISO-COM adapter with the current version of VAG-COM..

this is my first time tring to connect to the engine, the check eng light came on a few weeks ago..

VAG-COM normally works fine with those old V6's.

However, that engine is likely the only thing in the car that uses the L-Line. Check connection between L-line and K-line at diagnostic socket and appropriate pins of ECU.

The L-line output on the old ISO-COM is not protected against overcurrents. It is possible to kill that output if you connect it to +12 by mistake using the old "ugly" 2x2 adapter. L-ine output can be checked with a 1K resistor and a garden-varietry LED (about $1.99 in parts from Radio Shack).

-Uwe-

for checking the L-line with the led
am I checking the port on the car or the ISO-COM

On your car, near the 2x2 diagnostic soctes, there should be two screw terminals labelled K and L. Connect a 1K resistor and LED between the one marked L and +12 like this:

L -----|<---/\/\/\/\/\/------ +12

The LED should blink when VAG-COM is trying to establish a connection with your engine.

-Uwe-