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 MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1409 (CELLULAR SYSTEM, ENTERTAINMENT SYSTEM, AND NAVIGATION SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESUNABLE TO CONTACT ONSTAR CALL CENTERCIRCUIT/SYSTEM VERIFICATION
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6
Circuit/System Verification
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Verification
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
- It is important to have the vehicle in an open outside area where a cellular call can be successfully placed and GPS data can be received from satellites.
- Placing an emergency call to the OnStar® Call Center should only be made if the diagnosis of the system leads to step 4. Immediately after an OnStar® advisor picks up the call, they should be told that this call is for diagnostic purposes only and there is no emergency.
- Press the OnStar® Call Center button. Verify a connection is not made with the OnStar® Call Center.
- If a connection is made with the OnStar® Call Center, go to Diagnostic Aids .
- Listen for other tones or cellular messages rather than the normal progression tones or the Unable to Contact OnStar® prompt.
- If no other tones or cellular messages are heard other than the normal progression tones or the Unable to Contact OnStar® prompt, go to Component Testing .
- Record all messages heard from the OnStar® Call Center button press.
- Press the OnStar® emergency button. Verify a connection to the OnStar® Call Center is made within 10 minutes.
- If a connection is not made within specified time, go to Component Testing .
- Hear all messages during the course of the tests available, and contact the General Motors Technical Assistance Center.
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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.