Retrieving Diagnostic Trouble Codes
WARNING: This page is about a different car, the 2002 Chevrolet Monte Carlo and 2002 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
See RETRIEVING DIAGNOSTIC TROUBLE CODES for 3.4L engine or RETRIEVING DIAGNOSTIC TROUBLE CODES for 3.8L engine under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article in FAULT ISOLATION in ENGINE PERFORMANCE.