2021 Toyota Sienna Hybrid Transmission and drivetrain Problems
- Complaints
- 2about this part
- Share
- 4%of 45 total for the year
- Median mileage
- —not reported
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 2 complaints about the transmission and drivetrain of the 2021 Toyota Sienna Hybrid, 4% of the 45 complaints for this model year.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“The car jerks when coming to a stop. Like when the regenerative system is disengaged it jerks. For the Adaptive cruise control the car will accelerate instead of braking when another car merges in front of you.”
NHTSA complaint #11717402, filed 2026-02“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 complaint #11746943, filed 2026-06Related service bulletins
- 10190469Mar 31, 2021TSB: Some 2021 model year Sienna Hybrid vehicles may exhibit a depleted 12V auxiliary battery when in IG-OFF due to a condition in which the Hybrid Vehicle Electronic Control…
Transmission and drivetrain: other model years
Other parts of the 2021 Toyota Sienna Hybrid
13 complaintsBrakes
9 complaintsSeats
5 complaintsBody and structure
5 complaintsVisibility (wipers, defrost, mirrors)
5 complaintsElectrical system
4 complaintsEngine
3 complaintsOther or unknown
3 complaintsExterior lighting
2 complaintsSuspension
2 complaintsBack-over prevention (rear camera)
1 complaintsForward collision avoidance
1 complaints
← All problems reported for the 2021 Toyota Sienna Hybrid
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 31, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology