Scan Tool Does Not Communicate With Class 2 Device: Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2000 GMC Yukon XL, 2000 GMC Yukon, 2000 GMC Sierra, 2000 Chevrolet Tahoe, and 2000 Chevrolet Suburban. However, it is still accessible from the selected car via links, so may be relevant.
Modules connected to class 2 serial data line monitor serial data communications during normal vehicle operation. Operating information and commands are exchanged between modules. Connecting scan tool to Data Link Connector (DLC) allows communication with modules for diagnostics. DTCs may be set due to this symptom and during testing procedure. Complete testing procedure to ensure that all DTCs are diagnosed and cleared.