Test B: Scan Tool Does Not Communicate With Class 2 Device: Description
WARNING: This page is about a different car, the 2002 Pontiac Grand Am and 2002 Oldsmobile Alero. 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. Engine will not start when there is a complete malfunction of Class 2 serial data line while engine is off. DTCs may set due to this symptom and during this diagnostic procedure. Complete diagnostic procedure to ensure all DTCs are diagnosed and cleared from memory.