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
- Ignition OFF, disconnect the harness connector at the B24 Cellular Phone Microphone. Ignition ON.
- Test for 9 - 11 V between the signal circuit terminal B and ground.
- If less than 9 V
- Ignition OFF, disconnect the X1 harness connector at the K74 Human Machine Interface Control Module.
- Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground in the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K74 Human Machine Interface Control Module.
- If greater than 11 V
- Ignition OFF, disconnect the X1 harness connector at the K74 Human Machine Interface Control Module. Ignition ON.
- Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V, replace the K74 Human Machine Interface Control Module.
- Go to next step: If between 9 - 11 V
- Test for less than 1 V between the signal circuit terminal A and ground.
- If greater than 1 V
- Ignition OFF, X1 harness connector at the K74 Human Machine Interface Control Module. Ignition ON.
- Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage in the circuit.
- If less than 1 V, replace the K74 Human Machine Interface Control Module.
- Go to next step: If less than 1 V
- Ignition OFF, disconnect the X1 harness connector at the K74 Human Machine Interface Control Module.
- Test for infinite resistance between the B24 Cellular Phone Microphone signal circuit terminal A and ground.
- If less than infinite resistance
Repair the short to ground in the circuit
- Go to next step: If infinite resistance
- If less than infinite resistance
- Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater
Repair the open/high resistance in the circuit
- Go to next step: If less than 2 Ω
- If 2 Ω or greater
- Replace the B24 Cellular Phone Microphone.
- Ignition ON, infotainment system ON.
- Begin voice recognition for the infotainment system and clearly speak one of the available commands.
- Verify the infotainment system responds correctly to the command.
- If the infotainment system does not respond correctly to the command.
- Clearly speak a different command.
- Verify the infotainment system responds correctly to the command.
- If the infotainment system does not respond correctly to any commands, replace the K74 Human Machine Interface Control Module.
- Go to next step: If the infotainment system responds correctly to the command.
- Refer to the Owners Manual and/or the Navigation System Owners Manual for hints on speaking commands.
- Go to next step: If the infotainment system responds correctly to the command.
- 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.