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Diagnostic Procedure

  1. Connect scan tool to the DLC. The DLC is located on lower left side of instrument panel, near steering column. If scan tool powers up, go to next step. If scan tool does not power up, diagnose scan tool concern. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  2. Turn ignition switch to RUN position. Attempt to establish communication with the BCM or PCM. Does the scan tool communicate with the BCM or PCM? If so, go to next step. If not, diagnose body control system. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
    NOTE: If vehicle is a 2001 model year, go to step  4 . If vehicle is a 2002 model year, go to next step.
    3. NOTE: The engine may start during the following step. Turn engine off as soon as you have observed the CRANK POWER mode.
  3. Access the IGNITION SWITCH parameter in the BCM inputs data display list. Rotate the ignition switch through all positions while observing the ignition switch power mode parameter. Does the ignition switch parameter reading match the ignition switch position for all switch positions? If so, go to next step. If not, check for power mode mismatch concern. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  4. Select the BCM and PCM display DTCs function on the scan tool. Does the scan tool display any DTCs? If so, go to next step. If not, attempt diagnosis by symptom. See SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING.
  5. If "U" series DTCs (communication DTCs) are not retrieved, go to next step. If "U" series DTCs are retrieved, diagnose body control system. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  6. Does the scan tool display DTC B1000? If so, See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If not, go to next step.
  7. Does the scan tool display DTC P1819, P1820, P1822, P1823 or P1825? If so, diagnose DTCs as necessary. See appropriate DIAGNOSIS article. If not, go to next step.
  8. Does the scan tool display DTC B2712 or B3713 ? If so, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If not, attempt diagnosis by symptom. See SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING.
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