What 36 owners told NHTSA about the 2021 Toyota Sienna

FAILURE: Blind spot monitor module failed due to a corroded internal electrical connector. The failure disabled both the Blind Spot Monitor (BSM) and Rear Cross-Traffic Alert (RCTA). Both remain inoperative. The failed component has not been replaced and is available for inspection. SAFETY RISK: Two active safety systems are disabled. The vehicle no longer warns of vehicles in the blind spot during lane changes, and no longer warns of cross traffic when backing out of parking spaces or driveways. WARNING LAMPS: Yes. Multiple warning lamps illuminated simultaneously in February 2026, including BSM and RCTA malfunction messages. No prior symptoms or gradual degradation. CONFIRMED BY DEALER: Yes. A Toyota dealer diagnosed the corroded connector as the cause. Repair quoted at approximately $2,500-$3,000. Repair not performed. INSPECTED BY MANUFACTURER: Diagnosed by a Toyota dealer. Goodwill assistance was requested from Toyota and declined, on the stated grounds that the vehicle had not been regularly serviced at a Toyota dealer. NOT A WEAR ITEM: A sealed electrical connector that corrodes to failure is a component defect. No step in the manufacturer's published maintenance schedule inspects, services, or protects this connector — no owner action could have prevented it, and service history has no bearing on a connector that no service procedure touches. Vehicle purchased new September 2021; failure occurred at approximately [XXX] of age. REQUEST: Request that ODI evaluate whether the BSM sensor and connector design used on this vehicle is inadequately sealed against moisture intrusion, resulting in premature failure of two active safety systems. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI 11750096

Unexpected failure of the acceleration pedal to accelerate from a complete stop to a go at an intersection. The electric vehicle (EV) motor began accelerating up to about 3 mph than instantly had a failure to accelerate, even with the gas pedal continuously pushed to the floor. After about 4 to 5 seconds the engine kicked on and began accelerating. The failure seemed to occur during the EV motor swapping over to the gas powered engine. This has been the fourth occurrence and can be extremely dangerous at intersections with oncoming traffic. No fault codes or check engine lights came on.

NHTSA ODI 11746943

The contact owns a 2021 Toyota Sienna Hybrid. The contact stated that the vehicle was experiencing inaccurate fuel gauge readings. The contact stated while starting the vehicle, the fuel gauge reading displayed that the fuel tank was empty; however, while the contact was attempting to refuel the vehicle at the gas station, she became aware that the fuel tank was not empty and that there was sufficient fuel in the vehicle. The vehicle was taken to the CarMax dealer, where it was driven and refueled several times; however, the failure could not be replicated. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 50,300.

NHTSA ODI 11596197