Third-Row Seat Stowage Failure

Third-row seats fail to remain securely stowed in their designated position. Estimated repair cost: $200 - $700.

Airbag System Malfunctions

Airbag warning lights illuminate, or airbags deploy unexpectedly or fail to deploy after a collision. Estimated repair cost: $400 - $1,200.

Electrical System Issues

Intermittent power loss, malfunctioning infotainment screens, or other electrical gremlins. Estimated repair cost: $100 - $800.

Skid Control ECU Software (Recall)

Potential issues with the Electronic Stability Control (ESC) system. Estimated repair cost: Covered by recall.

CARFOCALvehicle research

2021 Toyota Sienna Maintenance guide

Name: Maintenance dataset for 2021 Toyota Sienna
Creator: Carfocal

v1.0Updated May 30, 2026Ethan Miller4 Sources Analyzed

MAINTENANCE SUMMARY

The 2021 Toyota Sienna requires diligent maintenance, with a strong emphasis on the braking system due to frequent complaints of unexpected acceleration or disengagement. Regular inspections of the third-row seats for secure stowage and checks of the airbag system are also crucial.

View Critical Issue: Service Brakes (Unexpected Acceleration/Disengagement)

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Reliability Score

Est. Annual Maintenance Cost

$1,000 - $1,500

TSBs & Recalls

6 TSBs | 12 Recalls

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Key Takeaways

The braking system is the most critical area for inspection due to frequent complaints of unexpected acceleration or disengagement.
Owners must ensure the third-row seats are securely stowed, as failures to remain in place have been reported.

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Critical service intervals

Common failure analysis

Symptoms and prevention guidance