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
2019 Buick Envision BaseSECTION Circuit/System Testing
NOTE:
- The vehicle may be equipped with sectioned coax. Test each section and replace only the faulty section, not the entire length of coax.
- The following verification requires the vehicle to be outside with an unobstructed view of the southern sky. Allow 5 min after turning the ignition ON for the GPS satellites to acquire vehicle signal.
- Verify the OnStar Generation you are working on by using a scan tool under Selected Vehicle Configuration/Telematics Communication Interface Control Module. Failure to use the correct document will result in incorrect diagnoses.
- Ignition OFF and all vehicle systems OFF, disconnect the cellular GPS coax cable connector at the K73 Telematics Communication Interface Control Module. It may take up to 2 min for all vehicle systems to power down.
- Connect the EL-49903-1 Test Antenna, Navn-Cell Comn to the K73 Telematics Communication Interface Control Module. Place the test antenna on the roof of the vehicle, ignition ON.
- Verify the DTC does not set while operating the vehicle within the conditions for running the DTC.
- If the DTC sets
Replace the K73 Telematics Communications Interface Control Module.
- Go to next step: If the DTC does not set
- If the DTC sets
- Ignition OFF.
- Disconnect the EL-49903-1 Test Antenna, Navn-Cell Comn from the K73 Telematics Communication Interface Control Module
- Disconnect the GPS and cellular coax cable connector at the T4G Cellular Phone, Navigation, and Digital Radio Antenna.
Test the coax cable. Refer to Component Testing.
- Test the coax cable between the K73 Telematics Communication Interface Control Module and the T4G Cellular Phone, Navigation, and Digital Radio Antenna. Refer to Component Testing.
- If the coax cable does not pass the test
Replace the coax cable.
- Go to next step: If the coax cable passes the test
- If the coax cable does not pass the test
- Test or replace the T4G Cellular Phone, Navigation, and Digital Radio Antenna.
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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.