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Home >> Buick >> 2003 >> Century Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 3.1L Engine >> Drive Cycles >> Inspection/Maintenance Heated Oxygen Sensor Heater System Set Procedure >> Diagnostic Procedure
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Diagnostic Procedure

  1. Perform I/M system check. See INSPECTION/MAINTENANCE SYSTEM CHECK . After performing I/M system check, go to next step.
    2. NOTE: Whenever ignition switch is turned to RUN position, ignition voltage is supplied to HO2S heaters. After verifying enable criteria, turn ignition switch to OFF position for approximately 5 minutes to allow sensors to cool before continuing with test.
  2. Pre-program scan tool with vehicle information before ignition switch is turned to RUN position. Ensure vehicle is within enable criteria. Set vehicle parking brake. Verify transmission is in Park for A/T and Neutral for M/T. Turn OFF all accessories. Start the engine and allow it to idle for 2 minutes or until I/M SYSTEM STATUS indicator updates to YES. If HO2S HEATER SYSTEM STATUS updates to YES, go to step  5. If HO2S HEATER SYSTEM STATUS does not update to YES, go to next step.
  3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not indicate any failed DTCs, go to next step.
  4. Determine which DTCs are required to run to complete this test. See INSPECTION/MAINTENANCE SYSTEM DTCS . 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 the scan tool. Operate vehicle within the Conditions for Running Test. See CONDITIONS FOR RUNNING TEST . Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat this procedure for any additional required DTCs that have not run. Using scan tool, observe the I/M System Status display. Did the HO2S Heater System Status update to YES? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are set, system is okay at this time.
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