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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 218 (ENGINE CONTROL SYSTEM - SELF-DIAGNOSTICS)DRIVE CYCLESINSPECTION/MAINTENANCE CATALYST SYSTEM SET PROCEDUREDIAGNOSTIC PROCEDURES
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Diagnostic Procedures

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION 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 the engine. Important: For this test to run, vehicle must operate in the following conditions:
    • Idle engine for one minute after reaching operating temperature of 158°F (70°C).
    • Acceleration at part throttle to 35-55 MPH (56-90 km/h) with this speed maintained for 2-3 minutes or until I/M system status updates to YES.
    • Using scan tool, observe I/M system status display.
    Did the catalyst 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 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 the DTC. See CONDITIONS FOR RUNNING . Repeat procedure until scan tool indicates the diagnostic test has run. Using scan tool, observe I/M System Status display. Did the Catalyst System Status update to YES? If yes, go next step. If no, see 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? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay at this time.
RENDER: 1.0x

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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.