Engine Electrical Diagnostic System Check

Perform battery inspection test. See BATTERY TESTING & INSPECTION under ON-VEHICLE TESTING. If battery passes inspection, go to next step.
Connect scan tool to Data Link Connector (DLC). If scan tool powers up, go to next step. If scan tool does not power up, see SCAN TOOL DOES NOT POWER UP under SYSTEM TESTS in BODY CONTROL MODULES - PARK AVENUE article in ACCESSORIES & EQUIPMENT.
Turn ignition switch to RUN position. Using scan tool, attempt to communicate with Body Control Module (BCM), Climate Control Panel (CCP), Instrument Panel Cluster (IPC), Memory Seat Module (MSM), OnStar (ONS) and Powertrain Control Module (PCM) on class 2 serial data circuit. If scan tool communicates with all modules, go to next step. If scan tool does not communicate with all modules, see SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE BODY under SYSTEM TESTS in BODY CONTROL MODULES - PARK AVENUE article in ACCESSORIES & EQUIPMENT.
Using scan tool, select DISPLAY DTCs function and retrieve DTCs for each module. Record all displayed DTCs, DTC status, and module which set the DTC. If scan tool displays DTCs, go to next step. If scan tool does not display DTCs, repair charging system by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.
If scan tool does not display DTCs which begin with "U", go to next step. If scan tool displays DTCs which begin with "U", see DIAGNOSTIC TROUBLE CODES in BODY CONTROL MODULES - PARK AVENUE article in ACCESSORIES & EQUIPMENT.
If scan tool displays DTCs B1982, B1983 or B2348, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS table. If scan tool displays any other DTCs which begin with "B", see DIAGNOSTIC TROUBLE CODE DEFINITIONS in BODY CONTROL MODULES - PARK AVENUE article in ACCESSORIES & EQUIPMENT.