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 266 (BODY CONTROL MODULES)REMOVAL & INSTALLATIONPOWERTRAIN CONTROL MODULE (PCM)REMOVAL & INSTALLATION (3.5L)
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Removal & Installation (3.5L)
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Removal & Installation (3.5L)
WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
- Turn ignition switch to OFF position. Remove rear seat cushion to access battery. Disconnect negative battery cable. PCM is located in air cleaner box, on left side of engine compartment. See Figure. Remove driver side strut brace. Disconnect air duct from throttle body.
- Disconnect intake air temperature sensor and mass airflow sensor connectors. Loosen air cleaner cover retaining screw. Remove air cleaner cover. Lift PCM from air cleaner housing. Disconnect PCM harness connectors. Remove PCM from engine compartment.
- To install, reverse removal procedure. Tighten PCM connector screws to 71 INCH Lbs. (8 N.m). Replacement PCM must be programmed and Crankshaft Position (CKP) system variation learn procedure must be performed. See POWERTRAIN CONTROL MODULE under PROGRAMMING.
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.