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.
OnStar® Module Reprogramming
Important: Follow the instruction set for the part that you are replacing. Both the Vehicle Interface Unit (VIU) and Vehicle Communication Unit (VCU) have a specific set of unique numbers that tie the module to the vehicle it resides in. These numbers, the 10 digit Station Identification and 11 digit Electronic Serial Number, are used by the National Cellular Network and OnStar to identify the specific vehicle. Because these numbers are tied to the Vehicle Identification Number of the vehicle, these parts should NOT be exchanged with those of another vehicle. Failure to perform these steps will prevent the OnStar® features from functioning and will result in a customer return for repair.
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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