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 620 (CELLULAR COMMUNICATION SYSTEM)
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Section 620 (Cellular Communication System)
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Section 620 (Cellular Communication System)
WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
- Specifications
- Schematic and Routing Diagrams
- Component Locator
- Diagnostic Information and Procedures
- Diagnostic Starting Point - Cellular Communication
- Diagnostic System Check - Cellular Communication
- Scan Tool Data List (F1)
- Scan Tool Data Definitions (F1)
- Diagnostic Trouble Code (DTC) List (F1)
- DTC B2455: Cellular Microphone Signal
- DTC B2470: Vehicle Communication Interface Module Detects No Cellular Signal
- DTC B2476 (F1): Keypad Signal Circuit Voltage Less Than 2.8 Volts
- DTC B2482: Button Is Depressed Or Stuck For More Than 15 Seconds
- DTC B2483 or B2484: Vehicle Communication Interface Module Does Not Detect A Navigation Signal
- Symptoms - Cellular Communication (F1)
- OnStar One or More Buttons Inoperative (F1)
- Unable to Contact OnStar Call Center (F1)
- Microphone Inoperative - Caller Cannot Be Heard (F1)
- Voice Recognition Inoperative
- OnStar Button LED Inoperative (F1)
- No (or Noisy) OnStar Audio (F1)
- Repair Instructions
- Description and Operation
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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.