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Home >> Oldsmobile >> 2001 >> Bravada >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 4.3L >> Inspection/Maintenance Procedures >> Inspection/Maintenance Heated Oxygen Sensor (Ho2S) System Set Procedure >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
    2. NOTE: Whenever ignition is turned on, ignition positive voltage is supplied to HO2S heaters. After verifying the enable criteria, turn ignition off for about 5 minutes to allow sensors to cool before continuing with test.
    • Preprogram scan tool with vehicle information before turning ignition on.
    • Ensure vehicle is within the conditions for running DTC.
    • Set parking brake.
    • Verify transmission is in Park (A/T) or Neutral (M/T).
    • Turn off all of accessories (e.g., A/C, blower fan, etc.).
    • Start and allow engine to idle.
    • Operate engine at idle until I/M System Status indicator updates to YES.

    If HO2S heater system status updates to YES within 2 minutes, go to step  5. If HO2S heater system status does not update to YES within 2 minutes, go to next step.

  3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not display any DTCs, go to next step.
    4. NOTE: Refer to INSPECTION/MAINTENANCE SYSTEM DTC TABLE  to determine which DTCs are required to run in order to complete this test.
  4. Using scan tool, observe the NOT RAN SINCE CODE CLEARED display. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the Specific DTC menu of scan tool. Operate vehicle within the conditions for running this procedure. See ENABLING CRITERIA . Repeat the procedure until scan tool indicates the diagnostic test has run. Repeat this step for any additional required DTCs that have not run. Using scan tool, observe I/M System Status display. If HO2S Heater System Status updates to YES, go to next step. If HO2S Heater System Status does not update to YES, see DIAGNOSTIC AIDS .
  5. Using scan tool, observe emission related DTC portion of I/M System Status display. If scan tool indicates any emission related DTCs set, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are displayed, system is okay.
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