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.
Circuit/System Verification
For the GPS antenna to receive a clear signal, it is necessary that the antenna has an unobstructed line of sight to at least 3 satellites, which means the reception is best when there is open sky above the vehicle for at least 180°.
- Ignition - On / Vehicle - In Service Mode
- Verify the function: Exterior Lighting - ON - All Doors Lock/Unlock - Horn - ON
- If a condition exists
Refer to: Diagnostic System Check - Vehicle
- Go to next step: If all functions work properly
- If a condition exists
- Perform a test call with OnStar and verify the OnStar advisor can clearly hear you.
- If the component does not work as specified
Refer to: Unable to Contact OnStar Call Center
- Go to next step: If the component works as specified
- If the component does not work as specified
- Verify the correct operation: OnStar - Command State = Exterior Lighting - ON - All Doors Lock/Unlock - Horn - ON
- If the component does not work as specified
Replace the component: K73 Telematics Communication Interface Control Module
- Go to next step: If the component works as specified
- If the component does not work as specified
- All OK.
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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.