Engine Electrical Diagnostic System Check

NOTE: The presence of DTCs which begin with "U" indicate some other module on class 2 serial data circuit is not communicating.

Load test battery. If battery passes load test, go to next step. If battery does not pass load test, service battery as necessary and go to next step.
Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. If scan tool powers up, go to next step. If scan tool does not power up, go to TEST A: SCAN TOOL DOES NOT POWER UP under SYSTEM TESTS.
Turn ignition switch to RUN position. Using scan tool, attempt to communicate with Body Control Module (BCM), Instrument Panel Cluster (IPC) and Powertrain Control Module (PCM). If scan tool communicates with all modules, go to next step. If scan tool does not communicate with all modules, go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS.
Using scan tool, select DISPLAY DTCS function for all modules. Retrieve and record all displayed DTCs, their status and which module set DTC. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, repair engine electrical concern by symptom. See appropriate GENERATOR & REGULATOR article in STARTING & CHARGING SYSTEMS.
If scan tool does not display any DTCs which begin with a "U", go to next step. If scan tool displays any DTCs which begin with a "U", go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS.
If scan tool display DTC B1000, go to DTC B1000: BODY CONTROL MODULE MALFUNCTION under DIAGNOSTIC TESTS. If scan tool displays any other DTCs, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .