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 1604 (CELLULAR COMMUNICATION SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESONSTAR ALWAYS ON
2003 Chevrolet TrailBlazer 4.2 S, 4WD
OnStar Always On
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION OnStar Always On
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Cadillac Escalade EXT. However, it is still accessible from the selected car via links, so may be relevant.
OnStar Always On
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: OnStar Schematics DEFINITION: The OnStar® system remains on after the ignition has been turned off. |
|||
| 1 | Did you perform the Cellular Communication Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Cellular Communication |
| 2 |
|
Go to Step 3 | Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS |
| 3 | Repair the ignition 1 voltage circuit for a short to battery voltage. Refer to CIRCUIT TESTING
and WIRING REPAIRS
. Did you find and correct the condition? |
Go to Step 4 | Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS |
| 4 | Operate the system in order to verify the repair. Did you correct the condition? |
System OK | Go to Step 2 |
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.