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Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. 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. After performing battery inspection, go to next step.
  2. Connect scan tool to DLC. See COMPONENT LOCATIONS  . Turn ignition switch to RUN position. If scan tool powers up, go to next step. If scan tool does not power up, see 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).
    • 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 DTCs which begin with "U", go to next step. If scan tool displays DTCs which begin with "U", perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  7. If scan tool displays DTC B1000, repair this DTC first. See BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool displays any other DTCs, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  .
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