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Home >> Cadillac >> 2007 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 28 (Engine Control System - Self-Diagnostics) >> Drive Cycles >> Inspection/Maintenance (I/M) Heated Oxygen Sensor (Ho2S) Heater 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 a 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.
    NOTE: Once engine is started, DO NOT turn OFF the engine for remainder of the procedure until test is complete.
  2. Start and idle engine. Ensure vehicle is within conditions for running specified in supporting text. See CONDITIONS FOR RUNNING . Set vehicle parking brake. Verify transmission is in Park for automatic transmissions and Neutral for manual transmissions. Turn OFF all accessories, e.g., A/C, blower fan, etc. Start engine and let idle. Idle engine until engine reaches operating temperature of at least 158°F (70°C). This may be up to 8-10 minutes depending on start up coolant temperature.

    For the remaining portion of this test to run, vehicle must operate in the following conditions:

    • Acceleration at part throttle to 30-50 MPH (48-80 km/h).
    • Speed maintained for 2 minutes or until I/M system status indicator updates to YES.
    Did the HO2S heater system status update to YES? If yes, go to step  5. If no, go to next step.

  3. Using scan tool, observe DTC information. Does scan tool indicate any failed DTCs? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go next step.
    NOTE: Refer to INSPECTION/MAINTENANCE SYSTEM DTCS  to determine which DTCs are required to run to complete this test.
  4. Refer to INSPECTION/MAINTENANCE SYSTEM DTCS  to determine which DTCs are required to run to complete this test. Operate vehicle within conditions for running DTC. See CONDITIONS FOR RUNNING . Repeat procedure until scan tool indicates diagnostic test has run. With a scan tool, observe I/M SYSTEM STATUS display. Did HO2S heater system status update to YES? If yes, go to next step. If no, go to DIAGNOSTIC AIDS .
  5. Using scan tool, observe emission related DTC portion of I/M system status display. Does scan tool indicate any emission related DTCs set? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay at this time.
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