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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1313 (ENGINE EXHAUST SYSTEM)REPAIR INSTRUCTIONSCATALYTIC CONVERTER REPLACEMENT (3.8L)REMOVAL PROCEDURE
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Removal Procedure

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Removal Procedure
WARNING: This page is about a different car, the 2002 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.

The three way catalytic converter is serviced by replacing the entire assembly. Always replace the gaskets at the front and rear flanges when servicing the three way catalytic converter assembly. Never reinstall the original gasket.

  1. Raise and support the vehicle. Refer to LIFTING & JACKING THE VEHICLE .
  2. Disconnect the heated oxygen (HO2S) sensor wiring harness connector and retainers.
    NOTE: To prevent internal damage to the flexible coupling of the catalytic converter assembly, the converter must be supported. The vertical movement at the rear of the catalytic converter assembly must not exceed 6 degrees up or down.
  3. Support the exhaust system.
  4. Remove the catalytic converter bolts.
  5. Remove the catalytic converter gasket.
    6. Fig 1: Catalytic Converter Gasket & Bolts
    G01704099Courtesy of GENERAL MOTORS CORP.
  6. Remove the exhaust manifold pipe stud nuts.
  7. Remove the three way catalytic converter.
  8. Remove the exhaust manifold pipe gasket at the exhaust manifold pipe studs.
    Fig 2: Exhaust Manifold Pipe Stud Nuts
    G01704100Courtesy of GENERAL MOTORS CORP.
  9. Remove the heated oxygen (HO2S) sensor. Refer to HEATED OXYGEN SENSOR .
    Fig 3: Heated Oxygen (HO2S) Sensor
    G01704101Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

NO RELATED

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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.