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Home >> Cadillac >> 2004 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 26 (Engine Control System - Self-Diagnostics) >> Drive Cycles >> Inspection/Maintenance Heated Oxygen Sensor/Oxygen Sensor (Ho2S/O2S) System Set Procedure >> Diagnostic Procedures
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Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Inspection/Maintenance (I/M) system check? If yes, go to next step. If no, go to INSPECTION/MAINTENANCE SYSTEM CHECK .
    2. WARNING: Road test vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.
  2. Ensure vehicle is within conditions for running. See CONDITIONS FOR RUNNING . Turn OFF all accessories, e.g., A/C, blower fan, etc. Start and idle engine. For this test to run, vehicle must operate in the following conditions:
    • Accelerate engine to 30-50 MPH (48-80 km/h) and cruise for 3 minutes after engine reaches operating temperature.
    • Deceleration to zero MPH.
    Idle engine for 2 minutes While the following criteria is maintained:
    • Service brake is depressed.
    • Automatic transmission in Drive.
    • Manual transmission in Neutral with the clutch pedal depressed.
    Accelerate at part throttle to 30-50 MPH (48-80 km/h) with this speed maintained for 30 seconds. Using scan tool, review I/M SYSTEM STATUS display. Did HO2S/O2S system status update to YES? If yes, go to step  5. If no, 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 indicate any failed DTCs, go to next step.
    4. NOTE: Refer to INSPECTION/MAINTENANCE SYSTEM DTCS  to determine which DTCs are required to run to complete this test.
  4. Operate vehicle within conditions for running DTC. See CONDITIONS FOR RUNNING . Repeat procedure until scan tool indicates the diagnostic test has run. With a scan tool, observe I/M SYSTEM STATUS display. Did HO2S/O2S system status update to YES? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  5. Using scan tool, observe emission related DTC portion of the I/M system status display. Does scan tool indicate any emission related DTCs set? If yes, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay at this time.
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