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Engine Electrical Diagnostic System Check

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform battery inspection test. See BATTERY TESTING & INSPECTION  under ON-VEHICLE TESTING. Go to next step.
  2. Connect scan tool to Data Link Connector (DLC). DLC is located below left side of instrument panel. Turn ignition switch RUN position. If scan tool powers up, go to next step. If scan tool does not power up, perform appropriate test. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
    3. NOTE: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
  3. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool. Rotate the ignition switch through all positions while observing the Class 2 Power Mode parameter. The ignition switch parameter reading should match the ignition switch position for all switch positions. If reading is as specified, go to next step. If reading is not as specified, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  4. Turn ON the ignition, with the engine OFF. Attempt to communicate with each of the following modules on the class 2 serial data circuit:
    • Body Control Module (BCM).
    • Instrument Panel Cluster (IPC).
    • Driver Information Center (DIC).
    • Powertrain Control Module (PCM).
    The scan tool should communicate with all modules on the class 2 serial data circuit. If communication is as specified, go to next step. If communication is as not specified, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  5. Using scan tool, select DISPLAY DTC function for each module. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, diagnose by symptom. See SYMPTOM INDEX  table under SYSTEM TESTS.
  6. If scan tool does not display any DTC's which begin with "U", go to next step. If scan tool displays any DTC's which begin with "U", perform appropriate test in accordance with DTC retrieved. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
  7. If scan tool displays DTC's which begin with "B", perform appropriate test in accordance with DTC retrieved. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display DTC's which begin with "B", perform appropriate test in accordance with DTC's retrieved. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  .
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