Test B: Scan Tool Does Not Communicate With Class 2 Device: Description
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2002 GMC Savana, 2002 Chevrolet Chevy Express, 2001 GMC Savana Special, 2001 GMC Savana Camper Special, and 2001 GMC Savana. However, it is still accessible from the selected car via links, so may be relevant.
Modules connected to the class 2 circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. Connecting a scan tool to the Data Link Connector (DLC) allows communication with modules for diagnostic purposes. DTCs may be set due to this symptom and during this diagnostic procedure. Complete entire diagnostic procedure in order to ensure all DTCs are diagnosed and cleared from memory.