2021 Buick Envision · Electrical & software
Electrical or software fault may disable vehicle functions
The communications gateway module incorrectly processes a loss of communication with the sensing diagnostic module (SDM), causing the air bag malfunction indicator light to inconsistently illuminate.
What the reviewed source says
Start with the documented condition, not a parts guess.
NHTSA campaign 21V421000 includes certain 2021 Buick Envision vehicles. General Motors, LLC (GM) is recalling certain 2021 Buick Envision, Cadillac CT4, CT5, Escalade, Escalade ESV, Chevrolet Tahoe, Corvette, Suburban, GMC Yukon, Yukon XL vehicles. The communications gateway module incorrectly processes a loss of communication with the sensing diagnostic module (SDM), causing the air bag malfunction indicator light to inconsistently illuminate. The air bag malfunction indicator light may fail to warn the driver of a problem with the air bag, increasing the risk of injury.
Words owners may use
Does this match the moment?
Symptoms in the pattern
- Warning messages, a blank display, a no-start condition or loss of a vehicle function may occur
- An open campaign appears when the complete VIN is checked
- Some recalled vehicles may show no advance warning before the component fails
Vehicles and scope
- 2021 Buick Envision
- NHTSA campaign 21V421000
- The manufacturer filing lists 285,622 potentially affected units across the complete campaign.
- VIN eligibility determines whether this recall applies to an individual vehicle
Manufacturer position
What the official procedure directs
The communications gateway module software will be updated by a dealer, or through an over-the-air (OTA) update, free of charge. Owner notification letters were mailed on July 1, 2021. Owners may contact Buick customer service at 1-800-521-7300, Cadillac customer service at 1-800-458-8006, Chevrolet customer service at 1-800-222-1020, or GMC customer service at 1-800-462-8782.
Safety recall eligibility is based on the VIN and campaign scope, not ordinary warranty mileage. Check the complete VIN even when the vehicle is outside its original warranty.
Original evidence
Open the documents behind this page.
Repair paths and safe checks
Separate the diagnosis from the action.
Use the official recall remedy
The communications gateway module software will be updated by a dealer, or through an over-the-air (OTA) update, free of charge. Owner notification letters were mailed on July 1, 2021. Owners may contact Buick customer service at 1-800-521-7300, Cadillac customer service at 1-800-458-8006, Chevrolet customer service at 1-800-222-1020, or GMC customer service at 1-800-462-8782.
Do not buy parts from the campaign description alone. VIN scope, superseded remedies and parts availability can change.
What owners reported
Did this repair fix the same symptom on your car?
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Check the complete VIN before arranging work
Enter the 17-character VIN in NHTSA's recall lookup and ask the manufacturer or an authorised dealer to confirm whether the campaign is open for this vehicle.
A year, make and model match does not prove that every vehicle is included. The VIN result controls eligibility.
What owners reported
Did this repair fix the same symptom on your car?
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Useful before authorizing work
Read the method beside the problem
These guides explain the safety and evidence checks that apply to this problem file.
Check recalls by VIN
A VIN search checks the displayed NHTSA records for an unrepaired safety recall associated with one vehicle. A model search shows only the wider campaign population.
Read guide ↗When a car is unsafe
A warning light does not always mean the same thing, but weak brakes or smoke leave little room for experimentation. Damaged tires and certain recall instructions can do the same.
Read guide ↗Why symptoms overlap
“It makes a weird noise” is useful human language. Diagnosis begins when that language is tied to the exact vehicle and its operating conditions.
Read guide ↗More for this model
Other reviewed Buick Envision conditions
2021 to 2023 Buick Envision · Electrical & software
Exterior lights may not operate correctly
The daytime running lights (DRLs) may not deactivate when the headlights are on.
2026 Buick Envision · Vehicle information
Incorrect safety information or certification label
The radio may not have been set to the correct status to download the electronic owner's manual during production.
2024 Buick Envision · Vehicle information
Incorrect safety information or certification label
As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 110, "Tire Selection and Rims.".