NHTSA service bulletin

NHTSA Service Bulletin 10188910: 2021 Toyota Sienna Hybrid

Official manufacturer communication context for 2021 Toyota Sienna Hybrid, with affected products, buyer checks and links into Carchieve recall, problem and VIN research.

NHTSA service bulletin 10188910 summary graphic for 2021 Toyota Sienna Hybrid
10188910NHTSA document ID
Manufacturer communicationcommunication type
1affected product rows
82/100quality score

Reviewed June 2026 from NHTSA manufacturer communication and service bulletin records. Carchieve is independent and not affiliated with any vehicle manufacturer or government agency.

Quick answer

TSB: Some customers may notice an abnormal brake feel in their 2021 model year Sienna Hybrid vehicle that could be described as a longer than usual brake pedal stroke. This may occur when the engine is off for more than five minutes after entering the vehicle and closing all doors before driving. The condition does not affect braking performance and will improve as the system performs learning cycles during vehicle operation. However, once the engine is turned off and the brake ECU goes to sleep, these learned values will be reset and the abnormal brake pedal feel will return. Follow the Repair Procedure in this bulletin to address this condition.

What this bulletin may mean before buying

Treat this as service research, not a verdict on one car. Before you buy, compare this communication with official recall campaigns, model-level owner complaint patterns, and the exact vehicle’s VIN-decoded specifications. A bulletin can help you ask a seller or dealer sharper questions about software updates, known repairs, warranty extensions and service history.

Affected products listed in this communication

MakeModelModel yearsBuyer note
ToyotaSienna Hybrid2021Ask for service records and run the exact VIN before purchase.

Buyer checklist

  1. Run the 17-character VIN and confirm the year, make, model, engine and equipment match the listing.
  2. Check recall campaign pages for safety actions that may require dealer repair.
  3. Compare this bulletin with common problem pages for the same model and component area.
  4. Ask the seller or dealer whether the bulletin procedure, update or inspection has already been completed.
  5. Use the used-car buying checklist and get an independent inspection.

Frequently asked questions

What is NHTSA service bulletin 10188910?

TSB: Some customers may notice an abnormal brake feel in their 2021 model year Sienna Hybrid vehicle that could be described as a longer than usual brake pedal stroke. This may occur when the engine is off for more than five minutes after entering the vehicle and closing all doors before driving. The condition does not affect braking performance and will improve as the system performs learning cycles during vehicle.

Is a service bulletin the same as a recall?

No. A recall is a safety campaign with a required remedy for affected VINs. A service bulletin or manufacturer communication usually describes diagnostic, repair, software, warranty or service information.

How should a used-car buyer use this bulletin?

Use it as a research signal. Compare it with recalls, owner complaints, service records, a VIN report and an independent inspection before buying.

Check the exact VIN before you buy

Model-level pages show public safety patterns. A full VIN report helps confirm the exact vehicle, decoded specs, recall applicability and buyer checks.

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