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
- It is necessary to inform the OnStar® Call Center advisor that this call is for vehicle diagnostic purposes.
- It is necessary 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.
- Ignition ON/vehicle in Service Mode.
- Verify that the horn, lights, and the door locks on the vehicle operate properly.
- If an applicable vehicle system does not operate properly
Refer to Diagnostic System Check - Vehicle .
- Go to next step: If all applicable vehicle systems operate properly
- If an applicable vehicle system does not operate properly
- Verify that a call can be successfully placed to the OnStar Call Center by pressing the blue OnStar button.
- If unable to contact the OnStar® call center
Refer to Unable to Contact OnStar Call Center
- Go to next step: If able to contact the OnStar Call Center
- If unable to contact the OnStar® call center
- Verify with the OnStar advisor that all remote functions (door locks, lights, and horn) work.
- If the remote functions do not operate when requested
Replace the K73 Telematics Communication Interface Control Module
- Go to next step: If the remote functions operate when requested
- If the remote functions do not operate when requested
- All OK.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
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