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What 10 owners told NHTSA about the 2026 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 (10)Crash / fire / injury (1)Body & structure (2)Seats (2)Visibility & wipers (2)Backup camera & sensors (1)Brakes (1)Driver assistance (1)Lights (1)Speed control (1)

1 of 10 complaints match · Speed control · clear filters

Jun 18, 2026Speed controlBrakesDriver assistance

Less than 1000 miles on my car i do not remember exact dates hence i have added todays date for incident date.All three incident happend in three different days. Scenario 1 two times. Scenario 2 one time --- SCENARIO 1: Curved Road / No Lane Markings --- Conditions: ACC set at 25 MPH on an undivided two-way road with no lane markings. Parked vehicles present at curves; oncoming traffic at safe distance. Issue: On two separate occasions, the vehicle applied sudden, significant braking without driver input while navigating curves. No imminent collision risk existed. The abrupt speed reduction created a rear-end hazard from following traffic. Reported to Toyota support: YES --- SCENARIO 2: Michigan Left Turn Lane / 40 MPH --- Conditions: ACC active at 40 MPH on a multi-lane road with a dedicated Michigan Left turn lane. Forward path in my lane was clear. Issue: A vehicle ahead moved into the Michigan Left turn lane and began decelerating. As my vehicle accelerated (path now clear) and was still slightly behind — approaching but not yet parallel to — the turning vehicle, the system applied brief unexpected braking. The turning vehicle then moved further forward to complete its Michigan Left maneuver ; my vehicle resumed normal speed when some diagonal distance had been seen. Reported to Toyota support: NO ACTION REQUESTED: Investigate whether Toyota Sienna's PCS/ACC (1) miscalibrates object detection on unmarked curved roads and (2) fails to distinguish lateral vehicles from forward obstacles. Software update or remedy may be warranted.

NHTSA ODI 11745053

Working with the data? Download all 10 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 2026 Toyota Sienna verdict →