Diesel Engine Control Module And DAH: Diagnostics
WARNING: This page is about a different car, the 2002 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.
If none of the systems can be contacted, the fault may be either in the car or the diagnostic tool. If the diagnostic tool can contact one of the systems concerned in another car, then the fault is in the car.
In this case, first make sure that the control module is awake (as described in the TECHNICAL DATA ). If it is awake then the fault is probably in the lead between the data link connector and the control module.