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10.0

really awful
Crashes / Fires:
1 / 0
Injuries / Deaths:
1 / 0
Average Mileage:
0 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2021 Toyota Sienna engine problems

engine problem

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2021 Toyota Sienna Owner Comments

problem #8

Jun 062024

Sienna

  • miles

A D V E R T I S E M E N T S

Sometimes when each of us 2 are slowing to a stop while applying the brake, the Sienna will lunge forward. This unexpected event may cause a rear-end collision if too close. Also, it is enough to cause us to hit our head on the head rest. Can-??t understand why this happening. We are sure we only have our foot on the brake and not the accelerator.

- Strawberry Plains , TN, USA

problem #7

Apr 242024

Sienna

  • miles
When my car is going down a steep hill and I have the brake applied, Suddenly the car will speed up and lurch forward instead of continuing to slow down. This is not how cars normally behave in the 30 years I have been driving. I could have slammed into the car in front of me. This has happened over 100 times. My vehicle has approximately 27,000 miles and I have mentioned it at the Toyota service center and it has been checked out and there are no issues that they see. No warning, lamps or messages appear at all

- Carlsbad, CA, USA

problem #6

Apr 142024

Sienna

  • miles
This incident had happened twice in the last 30 days. I have been stopped, then starting to accelerate after a stop sign, I push on the accelerator and the vehicle slows down, as if it-??s losing power for about 5 seconds. I do not release the accelerator and after the 5 seconds of what feels like no power, the van begins to accelerate like normal. This poses a severe safety risk while crossing intersections when you believe your vehicle should respond when pushing on the accelerator. I did not have any notifications pop up on my van, I was in an open intersection on both instances, with no one in front of me. Speed limit was about 5mph, coming off a complete stop. This is extremely dangerous, especially when your vehicle feels like it stalls without any reason. The gas pedal is completely non-responsive for 5 seconds.

- Monticello, MN, USA

problem #5

Mar 162024

Sienna

  • miles

A D V E R T I S E M E N T S

In the 2-1/2 years than I have owned and driven this vehicle, I've had no problems. On Saturday, [XXX], driving home from a 80 mile trip, as I deaccelerated to make a left turn onto my street (speed was 7mph) I tapped the break pedal and the vehicle went bonkers! The Sienna veered right at a high rate of speed that the front end cleared the curb; the back end smashed into the curb flattening both rear tires and damaging the metal hubcaps; the vehicle speed tore off the bumper and both rear panels. I was able to steer the vehicle: missing a large 2-foot high tree stump; two other large trees; a 10-foot high solid fence at the yard back. I then drove down the sidewalk to the next intersection and was finally able to slow down. This entire time, my foot was on the break, but the vehicle would not stop. The Sienna is now at Faulkners Collision Center in Mechanicsburg with virtually no front end damage but colossal rear damage. The vehicle had 5-full maintenance checks since purchase. I was not told of any suspected problems and never received a vehicle recall. I could have been killed or may have killed others as there is a playground on the corner of this block. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

- Shiremanstown, PA, USA

problem #4

Jul 242023

Sienna

  • miles
Since we have owned the vehicle (April 2021), we've had three separate incidences where, when pulling out into traffic from a stop, and the accelerator (gas pedal) is pushed, the vehicle begins to move, but then power is immediately lost, leaving you stuck for a moment. Each time has been temporary, and when the pedal is released and depressed again, the vehicle begins moving. However, this sudden loss of acceleration and few second delay in movement of the vehicle now in the path of oncoming traffic can lead to an accident. The most recent occasion happened on July 24, 2023. We've reported the problem to the dealer two times, the most recent today, July 28, 2023, with no resolution.

- Las Vegas, NV, USA

problem #3

Dec 132022

Sienna

  • miles
when braking the car lunges forward on its own. this has happened multiple times and others speak of it too

- Conroe, TX, USA

problem #2

Dec 032022

Sienna

  • miles
The vehicle gets a jolt of power or speed while braking slowly or coming to a stop. This could result into an accident. This was addressed to multiple Toyota dealers and the problem was unidentified or undetectable to the technician multiple times. The problem is reported by several Sienna forum users but it is not being fixed by Toyota dealers.

- Coppell, TX, USA

problem #1

Jul 242021

Sienna

  • miles
We were driving down the freeway when we got rear ended hard by a large pickup. Then we lost electrical and engine power. The brakes stopped working. The hazard lights stopped working. Luckily we were able to coast to a complete stop as there was no way to stop the car. The police came and took a report. Then the car was towed to a body shop. We're awaiting the insurance company adjuster for inspection.

- Palos Verdes Estates, CA, USA

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