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What 36 owners told NHTSA about the 2021 Toyota Sienna

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (36)Crash / fire / injury (2)Airbags (12)Brakes (6)Visibility & wipers (5)Body & structure (3)Electrical system (3)Engine (3)Seats (3)Lights (2)Suspension (2)Transmission & drivetrain (2)

3 of 36 complaints match · Engine · clear filters

Apr 11, 2026SuspensionEngine

We were stopped at a stoplight. As soon as we stepped on the gas pedal, there was a loud clunk sound and plastic parts started flying out from under the car. We immediately pulled over. Oil was spilling out everywhere. The transmission oil pump was laying on the inside of the engine compartment. We had towed to Toyota. They diagnosed a bent piston went through engine which also caused a hole in the transmission. I had it towed for a 2nd opinion. Neither toyota or the 2nd opinion had ever seen anything like it. My mechanic also said there are a bunch of other suspension parts that were damaged due to the violent stop of the engine. There are a few of the same incidents online in chat rooms. The car is totalled and we are out of a car now.

NHTSA ODI 11730547

Apr 3, 2026EngineFire

The contact owned a 2021 Toyota Sienna Hybrid. The vehicle was parked in the driveway when an explosion occurred; the vehicle burned down. The contact was inside the residence when a loud noise was heard, and the house "rocked." The contact ran to the front of the house to investigate and noticed that the vehicle was engulfed in flames. The fire damaged the driveway, melted the garage door, and melted a landscaping retaining wall. The fire damaged the post on the front porch. The contact and her family were unable to exit through the front door due to the fire and used the sliding kitchen door to exit the residence. The fire department was called to the scene. Per the contact, three fire trucks were at the scene. The fire department informed the contact that the fire went up to 3,000 degrees. The fire department concluded that the fire started from underneath the driver's back panel. The contact stated that the gas tank was underneath that area and believed the gas tank may have contributed to the fire. The towing company towed the vehicle to a towing yard, and it was later picked up and towed to an unknown location. The insurance company was notified and declared the vehicle a total loss. The manufacturer was made aware of the failure and advised the contact that an inspection was needed on the vehicle and asked for the location of the vehicle.  However, the contact was awaiting the results. The failure mileage was approximately 80,000.

NHTSA ODI 11729036

Mar 26, 2021Engine

TL* THE CONTACT OWNS A 2021 TOYOTA SIENNA HYBRID. THE CONTACT STATED WHILE ATTEMPTING TO MAKE A RIGHT TURN WITH THE ACCELERATOR PEDAL DEPRESSED, THE VEHICLE FAILED TO RESPOND. THE CONTACT STATED NO WARNING LIGHT WAS ILLUMINATED. THE CONTACT STATED THAT HE HAD EXPERIENCED THE FAILURE ON SEVERAL OCCASIONS. THE VEHICLE WAS NOT DIAGNOSED NOR REPAIRED. A DEALER WAS NOT CONTACTED. THE MANUFACTURER HAD NOT BEEN INFORMED OF THE FAILURE. THE FAILURE MILEAGE WAS APPROXIMATELY 100. THE VIN WAS NOT AVAILABLE.

NHTSA ODI 11404950

Working with the data? Download all 36 complaints as CSV · fetched from NHTSA July 19, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2021 Toyota Sienna verdict →