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 Testing
- Ignition/Vehicle & All vehicle systems - Off
- Disconnect the electrical connector: Cellular Phone Antenna Circuit - Coax Cable@K73 Telematics Communication Interface Control Module
- Connect the special tool: EL-49903 GM OnStar Antenna Diagnostic Tool Kit @K73 Telematics Communication Interface Control Module
- Ignition - On / Vehicle - In Service Mode
- Verify DTC B2470 is not set.
- If DTC B2470 is set
Replace the component: K73 Telematics Communication Interface Control Module
- Go to next step: If DTC B2470 is not set
- If DTC B2470 is set
- Ignition/Vehicle & All vehicle systems - Off
- Disconnect the electrical connector: Cellular Phone Antenna Circuit - Coax Cable@T4G Cellular Phone, Navigation, and Digital Radio Antenna
- Perform the following procedure/test: Coax Cable - Component Testing
Verify the procedure/test passes.
- Component Testing = Failed
Replace the component: Cellular Phone Antenna Circuit - Coax Cable
- Go to next step: If the components test normal
- Component Testing = Failed
- Replace the component: T4G Cellular Phone, Navigation, and Digital Radio Antenna
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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