2015 Toyota Sienna Complaints

ENGINE — Filed 05/22/2026

I am submitting this complaint to request that the National Highway Traffic Safety Administration (NHTSA) document and evaluate what may be a broader defect affecting certain Toyota Sienna vehicles and determine whether it presents a potential safety-related defect trend. My 2015 Toyota Sienna was diagnosed by an authorized Toyota dealership with an external rear-bank head gasket leak. A head gasket is a critical engine component, and failure can result in coolant loss, engine overheating, reduced engine performance, stalling, or complete vehicle disablement. These conditions may create a safety risk, particularly if they occur while driving in traffic or at highway speeds. An authorized Toyota dealership confirmed the diagnosis and submitted a goodwill assistance request to Toyota. The dealership noted my history as a repeat Toyota customer and recommended that assistance be provided. Toyota denied the goodwill request based on the vehicle's age and mileage. I subsequently appealed through Toyota's customer relations process, and the denial was upheld. I understand that NHTSA does not resolve individual warranty or customer-assistance disputes. My purpose in submitting this complaint is to request that NHTSA determine whether similar reports exist involving premature head gasket failures in this model year or related vehicles and, if warranted, evaluate whether a broader defect trend exists that could present a safety concern. Potential safety consequences include engine overheating, loss of power, stalling, and unexpected vehicle disablement. The vehicle has been maintained in accordance with manufacturer recommendations and has not experienced any overheating event that would reasonably explain a premature head gasket failure. Thank you for your consideration and for documenting this complaint as part of NHTSA's review of potential vehicle safety issues. Respectfully, Vehicle Owner

TIRES — Filed 07/01/2026

I have requested urgent warranty evaluation regarding two Kumho Solus TA51a tires installed on my Toyota Sienna (Model: Kumho Solus TA51a, Size: 235/60R17 102H, DOT: 1824) Both front tires are exhibiting abnormal tread chunking and visible surface shredding. The tires are relatively new (purchased about 1-1.5 years ago) and have not been heavily used (only riding this car occassionally, about 5000-7000 miles per year). Our 2 rear tires are Kumho tires of different model, and although older, they are performing fine and do not experience these issues so it seems to be an issue on this particular Solus TA 51a model Kumho tires. Because this is our family vehicle and we transport our children in it regularly, we are very concerned about the safety of continuing to drive on these tires. I also returned to the tire shop that sold and installed the tires. After inspecting them, the owner advised me to contact Kumho for a warranty evaluation, informing me that he received similar complaints from other customers (especially Toyota Sienna owners) using this tire model. While I no longer have the original purchase receipt, the dealer can verify that the tires were purchased from and installed by his shop. I reached out to Kumho Tires USA by completing their online contact form 2 wks ago, which informed a response within 48 hours, but I have not received any response. I called and left a voice message in their warranty department, and in their general customer service line earlier this week, but still not response. I even completed another contact form and also reached out by email, but still no response. Then I remembered my mom recently sharing a concern about her tires, and just found out that she had same 'chunking' issues on her tires, which happened to be the same Kumho Solus TA51a tires from the same tire shop. Her car is Toyota Camry, not a Sienna, so this is happening on this specific tire model across all types of cars they are installed to. Please help!

STEERING — Filed 06/15/2026

My 2015 Toyota Sienna has “Sticky” steering. When on a curve, like an highway curved ramp, the steering locks in place. I have to pull the steering wheel back to keep the car on track. When it sticks I can literally let go on a curve and it will hold it’s position. Even when driving straight this occurs. The steering wheel will stick in place requiring me to turn it to get the steering wheel to come back to the desired or correct position. I’m seeing that this is a regular problem for Toyota steering across multiple models. Having your steering get stuck in place has the potential to be a very serious safety issue. This may cause an accident and resulting death. The complete repair for this safety issue to the consumer is over $3000.00. This is ridiculous! This is my first Toyota. I think their reliability night be really over rated.

SEAT BELTS,UNKNOWN OR OTHER — Filed 05/22/2026

Rain water leaking into the parked vehicle on the driver and passenger seat belts, potentially weakening the belts and creating odor.

POWER TRAIN — Filed 04/21/2026

On April 15, 2026 Report filed with NHTSA from an accident-causing property damage due to a failure in the shifter mechanism while the vehicle was parked, ignition off, no keys in the vehicle and the brake pedal was NOT pressed. Manufacture initiated an investigation after we contacted their customer care line. Our vehicle was taken to a Toyota dealership on March 11, 2026. We received an email on April 13, 2026 stating Toyota's inspection did not identify any evidence that this incident was a result of a concern with the operation of our vehicles gear shift lever. We retrieved our vehicle from the dealership on April 20, 2026. On April 21, 2026 From our driveway the shift lever fell out of park into drive with the ignition off, no keys, and the brake pedal not pressed. Toyota claims no responsibility! How is this possible when they know there are active recalls for the same issue on earlier models? This is a massive public safety risk considering the vehicle can rollaway without the ignition even being on! I will continue to report this issue every time the shift lever falls out of park until resolved.

POWER TRAIN — Filed 04/21/2026

On April 15, 2026 Report filed with NHTSA from an accident-causing property damage due to a failure in the shifter mechanism while the vehicle was parked, ignition off, no keys in the vehicle and the brake pedal was NOT pressed. Manufacture initiated an investigation after we contacted their customer care line. Our vehicle was taken to a Toyota dealership on March 11, 2026. We received an email on April 13, 2026 stating Toyota's inspection did not identify any evidence that this incident was a result of a concern with the operation of our vehicles gear shift lever. We retrieved our vehicle from the dealership on April 20, 2026. On April 21, 2026 From our driveway the shift lever fell out of park into drive with the ignition off, no keys, and the brake pedal not pressed. Toyota claims no responsibility! How is this possible when they know there are active recalls for the same issue on earlier models? This is a massive public safety risk considering the vehicle can rollaway without the ignition even being on! I will continue to report this issue every time the Shift lever falls out of park until resolved.

POWER TRAIN — Filed 04/21/2026

On April 15, 2026 Report filed with NHTSA from an accident-causing property damage due to a failure in the shifter mechanism while the vehicle was parked, ignition off, no keys in the vehicle and the brake pedal was NOT pressed. Manufacture initiated an investigation after we contacted their customer care line. Our vehicle was taken to a Toyota dealership on March 11, 2026. We received an email on April 13, 2026 stating Toyota's inspection did not identify any evidence that this incident was a result of a concern with the operation of our vehicles gear shift lever. We retrieved our vehicle from the dealership on April 20, 2026. On April 21, 2026 From our driveway the shift lever fell out of park into drive with the ignition off, no keys, and the brake pedal not pressed. Toyota claims no responsibility! How is this possible when they know there are active recalls for the same issue on earlier models? This is a massive public safety risk considering the vehicle can rollaway without the ignition even being on! I will continue to report this issue every time the Shift lever falls out of park until resolved.

POWER TRAIN — Filed 04/21/2026

On April 15, 2026 Report filed with NHTSA from an accident-causing property damage due to a failure in the shifter mechanism while the vehicle was parked, ignition off, no keys in the vehicle and the brake pedal was NOT pressed. Manufacture initiated an investigation after we contacted their customer care line. Our vehicle was taken to a Toyota dealership on March 11, 2026. We received an email on April 13, 2026 stating Toyota's inspection did not identify any evidence that this incident was a result of a concern with the operation of our vehicles gear shift lever. We retrieved our vehicle from the dealership on April 20, 2026. On April 21, 2026 From our driveway the shift lever fell out of park into drive with the ignition off, no keys, and the brake pedal not pressed. Toyota claims no responsibility! How is this possible when they know there are active recalls for the same issue on earlier models? This is a massive public safety risk considering the vehicle can rollaway without the ignition even being on! I will continue to report this issue every time the Shift lever falls out of park until resolved.

POWER TRAIN — Filed 03/10/2026

The contact owns a 2015 Toyota Sienna. The contact stated that while the vehicle was parked, and the shifter lever was turned off, it unexpectedly fell down, causing the vehicle to shift into drive and roll down the street, where it crashed into a house. At the time of the incident, the vehicle was occupied by one three-year-old and two six-year-old children. One of the six-year-old occupants attempted to move the shifter into park while another attempted to steer the vehicle. The passenger-side sliding door was ajar. There were no warning lights illuminated. There were no reported injuries, fire, or airbag deployment. A police report was filed. The vehicle was taken to a local dealer; however, the failure was not diagnosed or repaired. The manufacturer was contacted, but declined the claim. The failure mileage was approximately 119,274.

STEERING — Filed 04/14/2026

The power steering has a notch or almost a stickiness when turning. In turns around interstate ramps the steering almost locks in place requiring physical effort to get the steering to straighten back out. Even driving in a straight line one can feel this notch like feeling where the steering wheel is not operating in a smooth manner. This gives me a serious concern over the safety of driving this vehicle. In researching this specific issue it is notable that Toyota issued a large scale recall on other models for steering issues exactly as I’m experiencing on my vehicle. It appears this overall safety concern extends beyond the vehicles listed in Toyota’s original power steering safety issue recall.