2002 Buick Regal GSFACTORY OEM SERVICE PROCEDURE

Inspection/Maintenance Catalyst System Set Procedure: Procedure

  1. Perform INSPECTION/MAINTENANCE SYSTEM CHECK . After performing inspection/maintenance system check, go to next step.
    2. CAUTION: 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 operating within Conditions for Running. Turn all accessories off. Start engine and allow to idle. Operate vehicle in the following manor:
    • Accelerate at part throttle to 55 MPH and maintain speed for 5 minutes.
    • Decelerate to zero MPH and allow engine to idle for 2 minutes while service brake is depressed, A/T in Drive and M/T in Neutral with clutch pedal depressed.

    Using scan tool, monitor I/M SYSTEM STATUS. If CATALYST SYSTEM STATUS is YES, go to step  5. If CATALYST SYSTEM STATUS is not YES, go to next step.

  3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see DIAGNOSTIC TROUBLE CODE INDEX  table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If scan tool does not indicate any failed DTCs, go to next step.
  4. Using scan tool, monitor DTC P0420. Operate vehicle within code enable criteria for DTC P0420. See DTC P0420: CATALYST SYSTEM LOW EFFICIENCY  under DIAGNOSTIC TESTS. Operate vehicle within Conditions for Running until scan tool indicates diagnostic test has run. Using scan tool, observe I/M SYSTEM STATUS. If catalyst system status is YES, go to next step. If catalyst system status is not YES, see DIAGNOSTIC AIDS .
  5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see DIAGNOSTIC TROUBLE CODE DEFINITIONS .
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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