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 1601 (BODY CONTROL SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDIAGNOSTIC TROUBLE CODE (DTC) LIST

2003 Chevrolet TrailBlazer 4.2 S, 4WD

Diagnostic Trouble Code (DTC) List

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Diagnostic Trouble Code (DTC) List

WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

DTC	Diagnostic Procedure	Module
B1000	DTC B1000	Audio Amplifier, BCM, DDM, FPDM, HVAC, IPC, LGM, MSM-Driver, Radio, RSA, SDM, VCIM, VTD
B1004	DTC B1004	VCIM
B1007	DTC B1007	VCIM
B1009	DTC B1009	VCIM
B1397	DTC B1397	BCM
B1420	DTC B1420	BCM
B1440	DTC B1440	BCM

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.