Recall 21V421 covers 285,622 2021 Buick, Cadillac, Chevrolet, and GMC vehicles with air bag warning-light software errors. Software update is free.
Chevrolet is recalling 285,622 2021 vehicles, including Suburban, Tahoe, Corvette, Envision, Escalade, Yukon, CT4, and CT5 models, because the communications gateway module can process air bag system communication loss incorrectly. The air bag malfunction light can fail to warn the driver of an air bag problem, increasing injury risk, and Chevrolet dealers will complete the repair free of charge.
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What's wrong?
The serial data gateway module on these 2021 Chevrolet models is the vehicle's message router. It passes data between major electronic systems, including the sensing diagnostic module, or SDM. The SDM monitors crash-sensing information and communicates with the air bag system, while the air bag malfunction indicator light tells the driver when that system has a fault.
In recall 21V421, the gateway module software does not correctly save information when communication with the SDM is lost. Because that fault is not stored the right way, the vehicle does not always tell the driver through the air bag malfunction indicator light. The problem is in the software logic, not in a broken switch or bulb.
There is no warning sign before failure. The affected warning light is the part that fails to give consistent notice, so a dark air bag light does not prove the SDM communication is normal.
Who's affected?
Covers 10 model lines, from full-size SUVs and a sports car to Cadillac sedans, tied to the serial data gateway module.
| 2021 Chevrolet Suburban | air bag system |
|---|---|
| 2021 Chevrolet Suburban | electrical system software |
| 2021 Cadillac Escalade Esv | air bag system |
| 2021 Cadillac Escalade Esv | electrical system software |
| 2021 Cadillac Escalade | air bag system |
| 2021 Cadillac Escalade | electrical system software |
| 2021 GMC Yukon | air bag system |
| 2021 GMC Yukon | electrical system software |
| 2021 Chevrolet Tahoe | air bag system |
| 2021 Chevrolet Tahoe | electrical system software |
| 2021 GMC Yukon Xl | air bag system |
| 2021 GMC Yukon Xl | electrical system software |
| 2021 Chevrolet Corvette | air bag system |
| 2021 Chevrolet Corvette | electrical system software |
| 2021 Buick Envision | air bag system |
| 2021 Buick Envision | electrical system software |
| 2021 Cadillac CT4 | air bag system |
| 2021 Cadillac CT4 | electrical system software |
| 2021 Cadillac CT5 | air bag system |
| 2021 Cadillac CT5 | electrical system software |
| Units affected | 285,622 |
| Field incidents | NHTSA has logged no field incidents to date. |
A matching year and model does not guarantee inclusion. Check your VIN to confirm whether this recall applies to your specific vehicle.
What's the safety risk?
A failed air bag malfunction indicator light can leave the driver without a warning when the air bag system has a problem, increasing the risk of injury. Schedule the software update soon, and ask the dealer whether the update is completed in person or over the air. Repair is free at any franchised Chevrolet dealer.
What should I do?
- Check your VIN to confirm your 2021 Chevrolet Suburban, Escalade Esv, Escalade, Yukon, Tahoe, Yukon Xl, Corvette, Envision, CT4, or CT5 is included in this recall.
- Contact a franchised Chevrolet dealer to schedule the free communications gateway module software update that fixes the air bag warning-light communication problem.
- Ask whether your vehicle receives the software update at the dealer or through an over-the-air update.
- Bring the owner notice if you have it. If not, reference recall number 21V421 when you call.
- Keep the repair appointment even if the air bag malfunction indicator light is off, because the light is the part that fails to warn consistently.
What happens at the repair
At the dealer, a Chevrolet technician updates the communications gateway module software so it correctly handles communication loss with the sensing diagnostic module. GM can also deliver the same software update over the air when the vehicle is set up for it. The software update is free of charge. GM used its general reimbursement plan on file for this recall, so documented out-of-pocket repairs tied to this software issue are handled through that standard plan. Bring repair paperwork or receipts to the service desk if you already paid for related work.
| Reimbursement | Reimbursement available |
|---|
Timeline
| June 3, 2021 | Dealer notification began |
|---|---|
| June 3, 2021 | Dealer notification ended |
| June 10, 2021 | NHTSA published the recall |
| July 1, 2021 | Owner notification mailed |
| July 19, 2021 | VIN-searchable in NHTSA's database — Check your VIN to see whether this recall applies to your specific vehicle. |
| July 19, 2021 | Interim owner notification (was planned for this date) |
Frequently asked questions
What is recall 21V421?
Recall 21V421 covers 285,622 2021 Chevrolet Suburban and related 2021 vehicles with communications gateway module software that incorrectly handles lost communication with the sensing diagnostic module. The air bag warning light can illuminate inconsistently. Chevrolet dealers update the software for free, including through an over-the-air update where available.
What should I do if my 2021 Chevrolet Suburban is on this recall?
Check your VIN to confirm your specific vehicle is included in recall 21V421. If it is, contact a franchised Chevrolet dealer and ask for the communications gateway module software update. Reference recall number 21V421 when you call. The repair is free.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost. For recall 21V421, the communications gateway module software update is free through a franchised Chevrolet dealer or through an over-the-air update where available.
What is the safety risk?
The safety risk is an air bag warning light that fails to consistently alert the driver to an air bag problem. That can leave a driver unaware of a fault in the supplemental restraint system, increasing the risk of injury. The free software update corrects the warning-light issue.
When were owners notified about recall 21V421?
Owner notification letters were mailed on July 1, 2021. If you bought the vehicle used or never received a letter, the VIN still decides whether the recall applies. Check your VIN, then schedule the free software update with a franchised Chevrolet dealer if your vehicle is included.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/21V421000 |
|---|---|
| Chevrolet customer service | 1-800-521-7300 |
| NHTSA recall # | 21V421 |
| NHTSA recall # (full) | 21V421000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Quarterly Report (PDF)
- Download Recall Report (PDF)
- Download Misc. Document (PDF)
- Download Recall Document (PDF) (PDF)
- Download Owner Notification Letter (PDF)
- Download Owner Notice (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 23, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →