2018 Toyota Sienna Complaints

POWER TRAIN — Filed 08/11/2026

Whining noise when accelerating, transmission shop reported discovery of damage to transmission upon removal and inspection of transmission.

POWER TRAIN — Filed 09/17/2026

Transmission whining above 20mph. Toyota customer care program [XXX] states my vehicle falls within timeframe but dealer and corporate will not honor repairs INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

ELECTRICAL SYSTEM — Filed 09/02/2026

Odometer Fraud. The contact purchased a 2018 Toyota Sienna. It was discovered that there was a mileage discrepancy. The vehicle was a private sale. At the time of purchase, the mileage was 49,000. While attempting to resell the vehicle, the Auto Check report indicated that the mileage was 324,000.

POWER TRAIN — Filed 06/01/2026

Vehicle: 2018 Toyota Sienna XLE AWD, VIN [XXX], approximately 112,000 miles. Component: Power Train / Automatic Transmission (UA80F 8-speed). The vehicle has developed a pronounced whining noise from the transmission that rises with road speed, accompanied by harsh/rough shifting. A Toyota dealer inspected the vehicle and diagnosed a failing transmission requiring replacement. The symptoms and diagnostic trouble codes match those described in Toyota TSB T-SB-0160-18 ("Transaxle Whine Noise, Harsh Shift, MIL ON, or Reduced Power") for the UA80 8-speed transmission. This is the same failure mode Toyota acknowledged in Customer Support Program ZJC, which attributes the defect to a washer/locking tab that was not sufficiently bent during assembly, allowing an internal nut to loosen and causing progressive internal damage. However, this vehicle's transaxle serial number falls outside the range covered by ZJC, so Toyota has not provided coverage despite the identical defect and symptoms. This represents a safety concern. Based on documented failures of this transmission across the UA80 platform, the condition can progress to loss of power, limp mode, or sudden loss of forward propulsion while driving — including at highway speed and without further warning — creating a risk of a crash or of being stranded in traffic. The vehicle has been maintained through authorized Toyota service. I am requesting that NHTSA investigate whether the UA80/UA80F transmission defect warrants a broader safety defect determination and recall, given the volume of similar complaints across affected model years INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

POWER TRAIN — Filed 06/04/2026

Since owning my 2018 Toyota Sienna, I have experienced hesitation and erratic shifting with my transmission. I have the UA80E transmission which upon research others are experiencing issues with as well. It appears Toyota is not fully acknowledging the problem. The problem is a safety issue as sometimes when you go to quickly accelerate (merging, making a turn while starting from a stop, etc) the transmission hesitates and doesn't engage for a few seconds. This is an ongoing problem with the transmission. Toyota really needs to fix these transmissions!

POWER TRAIN — Filed 02/01/2026

My 2018 Sienna had developed a whining noise when accelerating. After taking it in to the mechanic, they advised the transmission was failing. Estimated price tag of $6500-7000 to repair. The vehicle has less than 140K miles. Looking at different issues with this make/model and year, it seems like its rather common. I bought a Toyota for its reputation of getting at least 200K if not more miles. I called both the dealer and Toyota themselves. Both said too bad, so sad - nothing they could do for me.

POWER TRAIN — Filed 11/01/2025

The contact owns a 2018 Toyota Sienna. The contact stated that while driving 30 MPH and ascending a hill, the vehicle started making an abnormal whining sound and hesitated while accelerating. The vehicle was driven to the dealer to be diagnosed. The vehicle was diagnosed with transmission failure. The manufacturer was notified of the failure. The failure mileage was approximately 126,000.

POWER TRAIN — Filed 01/14/2026

Transmission has been whining. A P27137F Code appeared and the vehicle is only in 2WD mode currently. Concerned to drive vehicle due to further damaging transmission or getting stuck while on the road.

POWER TRAIN — Filed 10/29/2025

My husband and I bought this van brand new 6 years ago. We have taken very good care of it and have had it serviced only at the dealership. We haven’t had any problem with the van outside of regular maintenance. On 10/29/25, I had a van full of children when I felt a slip in my acceleration and a warning light came on that read, “ A malfunction in the electronic control of the engine, throttle, or automatic transmission has been detected. Contact your dealer in order to have your vehicle inspected immediately.” Thankfully, I was able to get it to the parking lot. The van didn’t leave that parking lot until the next morning when we took it directly to the dealership. That is when we were told the solenoid and the transmission had gone out. We had to have the whole thing replaced. The van only had 89,388 miles on it.

POWER TRAIN — Filed 08/04/2025

Transmission Whine and Hesitation. Low gear it will hesitate from stop. Know issue with this transmission. There should be a recall on all ua80 transmissions.

FUEL/PROPULSION SYSTEM — Filed 07/09/2025

Hi, I’d like to report a serious issue with my 2018 Toyota Sienna related to the recent fuel system recall. Since the repair, the vehicle has leaked all of its gasoline not once, but three separate times. One of those times, my family was inside the vehicle, and the smell of gas was overwhelming. The car wouldn’t start, and it was clearly an unsafe situation. Now the dealership is charging me $1,400 to replace the fuel pressure hose and clamp, which, after thorough research and review, appears to be directly related to the process they followed when replacing the recalled fuel pump. I’ve also tried contacting the service manager, but I haven’t received a call back. That’s why I’m now requesting that Toyota open a formal case to investigate this properly. I believe this repair should be covered, and I’m asking for support from Toyota directly.

ELECTRICAL SYSTEM — Filed 06/04/2025

Odometer Fraud. The contact purchased a 2018 Toyota Sienna. The contact stated that while attempting to register the vehicle, it was discovered that there was a mileage discrepancy. The vehicle was a dealer sale. At the time of purchase, the vehicle mileage was 57,000, and at the time of registration, it was discovered that the mileage was 175,152.

POWER TRAIN — Filed 04/24/2025

Whining sound coming from vehicle while in drive and accelerator is depressed. Confirmed by dealership that the transmission is failing and needs replacement.

UNKNOWN OR OTHER — Filed 02/08/2025

Power Sliding Door Cable broke but not covered on current service bulletin POL19-02 dated 06/19/2019 The door affected is the passenger sliding door on the drivers side of the vehicle.

ENGINE — Filed 09/09/2024

The contact owns a 2018 Toyota Sienna. The contact stated while driving at an undisclosed speed, the vehicle jerked and lost motive power. In addition, the contact stated that on several occasions the vehicle shut off independently. The vehicle was taken to the dealer; however, the failure could not be duplicated. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. In addition, the contact stated that the vehicle was taken to the dealer several times due to the failure. The contact stated that the failure began in 2019 but had become a persistent failure. The contact stated the vehicle was repaired under of an unknown recall and the fuel pump was replaced in 2020; however, the failure reoccurred. The manufacturer was not made aware of the failure. The failure mileage was unknown.

POWER TRAIN — Filed 07/30/2024

This is a reoccurring issue on numerous occasions but the transmission programming is a danger to drivers when it is in economy mode (the default setting when car starts up). The transmission constantly starts at a higher gear (3rd or 4th) and reduces throttle input from a stop. It makes for a slower takeoff when making a right turn on the stop sign because the engine would be lugging. Similarly when trying to overtake or merge lanes and you try to speed up the vehicle, the car does not want to downshift. The above mentioned problems are not there when eco-mode is disabled or the car is put into sport mode.

AIR BAGS — Filed 06/23/2024

The contact owned a 2018 Toyota Sienna The contact stated while driving 70 MPH, the contact was rear-ended and the vehicle lost control and the vehicle rolled over multiple times and fell into a ditch. The contact stated that the side air bags did deploy but the front air bags did not deploy vduring the accident. Medical attention was given to the contact and her family in which they were transported to the local emergency room. The contact stated she and her family suffered injuries the contact stated she had bruised ribs a contusion to her hip and her shoulder and a bruised lung. The contact daughter suffered a concussion neck and shoulder and was diagnosed with manubrium in her back. The contact son suffered a concussion contusion on his abdomen and neck. The contact spouse suffered an injured wrist finger injury and possibly broken ribs and all of the family suffered from whiplash. A police report was filed. The vehicle was towed to a local towing company and the vehicle was released to the insurance to be sent to CO-part. The dealer was contacted and the vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 117,000.

EQUIPMENT ADAPTIVE/MOBILITY — Filed 03/08/2019

The contact owns a 2018 Toyota Sierra equipped with a Joysceer USA Inc, Hand Control Unit. The contact stated that while operating the vehicle, the message advising to "Stop immediately" was displayed with the error code: 4209 BSM. The contact stated that later a second error code: 1069 SAM was displayed. The contact stated that the messages were due to a malfunction of the Hand Control Unit. The cause of the failures was not yet determined. The manufacturer and installation facility were contacted regarding the failure, but no response was provided. No identifying information was available for the equipment. The failure mileage was 2,000.

POWER TRAIN — Filed 04/05/2024

There has been a "whining" noise or "hum" upon acceleration noticed for several months to a year, could be longer, but getting worse over time. There is also a delay when pressing on gas for the vehicle to actually accelerate. I have had many instances where I am almost hit from behind because of this delay. Obviously the person's behind me have been following me entirely too closely, but nonetheless, scary. This is our primary vehicle for our family, which carries 4 precious boys. I am aware of the CSP already in place for this issue but have been told that my specific vehicle does not qualify for the customer protection program. That seems very odd given the amount of vehicle's listed as "affected"(83,700) sienna's and 66,500 highlanders. You cannot tell me that there are not more out there like mine that are having the SAME problems but being told "not covered". I do not think anyone should have to drive a vehicle with children in it that you are unsure when your transmission is just going to go out or fear getting hit from behind because of the delay in acceleration. Please please do something about this in order to hold toyota accountable!

ELECTRICAL SYSTEM,UNKNOWN OR OTHER — Filed 02/19/2024

I am an owner of a 2018 Toyota Sienna LE. The Vehicle has an issue with the safety connect system. Dealer first states that the cause is the data handling being off, called Toyota turned it on and waited for a few days and still did not work. Called Dealer to make an appointment for service, dealer advised that they reset the DCM twice and to wait 24-48 hours to see if it works. It still does not work. No lights present on the overheard place where the SOS Safety connect Button is located.

AIR BAGS — Filed 06/27/2021

The contact owned a 2018 Toyota Sienna. The contact stated while driving at 74 mph, a deer ran across the freeway, and as a result, the contact crashed into the deer. The air bags failed to deploy. A police report was filed. The contact sustained a sore shoulder but did not require medical treatment. The was not drivable and was towed back to their home address. The vehicle was not diagnosed or repaired. A dealer was contacted and informed the contact that they would run tests on the air bag once the vehicle was fixed. The manufacturer had not been informed of the failure. The failure mileage was 60,000. The VIN was unavailable.

AIR BAGS — Filed 06/01/2021

When turning left in a busy intersection, our van was struck by another vehicle on the front passenger corner of the car. The strike occurred with my van going about 10 mph, the other car going about 45 mph. All of the airbags deployed. When the airbags deployed, the coverings on the lights came off and the small lightbulb and silver casing projected out, scratching my son's arm. Nothing in the vehicle should break or become a projectile when the airbags deploy. I am not certain on the last few questions.

VEHICLE SPEED CONTROL — Filed 05/07/2020

UNINTENDED ACCELERATION WHILE REVERSING VEHICLE. VAN WENT FULL THROTTLE AND SPED UP IN REVERSE WHILE BACKING UP FROM MY DRIVE WAY AT HOME. *TR

UNKNOWN OR OTHER — Filed 12/02/2019

THE PCS STOPPED OUR VAN ABRUPTLY WITH NO WARNING AND DID NOT SLOW DOWN. CRUISE CONTROL SET AT 75 MPH NORTH BOUND ON TX HWY 69 BETWEEN ALTO AND RUSK, TX. NO RAIN SMOOTH ROAD LATE AT NIGHT ONLY THE CAR IN FRONT OF US. NO OTHER TRAFFIC. I SCREAMED. HUSBAND HAD FALLEN TO SLEEP AT THE WHEEL EVEN THOUGH WE HAD TAKEN A LONG NAP IN HUNTINGTON, TX. WE WERE ON OUR WAY BACK HOME FROM MY SISTER'S FUNERAL IN NEDERLAND, TX.. I COULD SEE INSIDE THE READ WINDOW OF THE CAR WE STOPPED BEHIND. NO COLLISION BUT INJURED MY NECK. HAVE MEDICAL RECORDS, WAS TREATED FOR NECK INJURIES IN JACKSONVILLE, TX AND TYLER, TX

AIR BAGS — Filed 04/19/2019

TAKATA RECALL (?) WE PURCHASED THIS VAN ON 4/18/2019, PREVIOUSLY THE VAN WAS A RENTAL. THE NEXT EVENING, GOING TO DINNER ON A FRIDAY NIGHT ABOUT 9 P.M. I WAS ON A 2 LANE ROAD IN A RURAL AREA, TRAVELING AT 60 MPH AND A DOG WALKED IN FRONT OF ME. I HAD NO TIME TO REACT. THE FRONT END OF THE VAN WAS LAYING IN THE ROAD, NOT DRIVABLE. AGAIN, A FRONT END COLLISION AND NO AIR BAG DEPLOYMENT! 2ND TOYOTA SIENNA, FIRST A 2017 AND NOW A 2018, BOTH RENTAL SALES, BOTH HAD FRONT END COLLISIONS AND BOTH HAD NO AIR BAG DEPLOYMENT. AT 60 MPH THERE'S NO REASONABLE EXCUSE FOR NO AIR BAG DEPLOYMENT.