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.
2021 Buick Envision Avenir, AWDFACTORY OEM SERVICE PROCEDURE
Reprogram ECU (UDD)
To program a replacement or an existing ECU, perform the following procedure:
- Ignition ON/Vehicle in Service Mode.
- Access the Service Programming System (SPS) and follow the on-screen instructions.
- Ignition/Vehicle OFF.
- On the SPS Supported Controllers screen, select P16 Instrument Cluster - Programming and follow the on-screen instructions.
- Clear DTCs.
NOTE:
Ensure programming of this module is performed using the EL-52100 (MDI 2). Using the EL-47955 (MDI) will result in a programming failure.
Factory Service Tools
Use the Manual With the Right Hardware
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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.