Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 906 (ENGINE EXHAUST SYSTEM)REPAIR INSTRUCTIONSCATALYTIC CONVERTER REPLACEMENT (2.2L)INSTALLATION PROCEDURE

2003 Chevrolet TrailBlazer 4.2 S, 4WD

Installation Procedure

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Installation Procedure

WARNING: This page is about a different car, the 2003 GMC Sonoma, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.

Install the heated oxygen sensors (HO2S) as necessary.
Install the catalytic converter and new gasket to the vehicle.
Install catalytic converter to the catalytic converter hanger.

Fig 1: Installing Catalytic Converter To Catalytic Converter Hanger
Courtesy of GENERAL MOTORS CORP.
Install the muffler and new gasket to the catalytic converter.
NOTE: Refer to FASTENER NOTICE in Cautions and Notices.
Install the muffler to the catalytic converter flange nuts.
Tighten

Tighten the muffler to the catalytic converter flange nuts to 35 N.m (26 lb ft).

Fig 2: Installing Muffler And New Gasket To Catalytic Converter
Courtesy of GENERAL MOTORS CORP.
Install the catalytic converter to the exhaust manifold pipe flange nuts.
Tighten

Tighten the catalytic converter to the exhaust manifold pipe flange nuts to 35 N.m (26 lb ft).

Fig 3: Installing Catalytic Converter To Exhaust Manifold Pipe Flange Nuts
Courtesy of GENERAL MOTORS CORP.
Connect the heated oxygen sensor (HO2S) electrical connection.
Lower the vehicle.

Fig 4: Connecting Heated Oxygen Sensor (HO2S) Electrical Connection
Courtesy of GENERAL MOTORS CORP.

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.