Chart F - DERM Cannot Communicate Through Serial Data Line: Notes
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 1994 GMC Vandura Special, 1994 GMC Vandura, 1994 GMC Rally Camper Special, 1994 GMC Rally, and 1994 Chevrolet Sportvan. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
To avoid air bag deployment and injury when trouble shooting system, only use test equipment specified in diagnostic charts. Under no circumstances should battery powered test equipment or test light be used. Carefully follow all instructions.