2015 Toyota Sienna

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

NHTSA ID

11751053

Incident

May 22, 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!

NHTSA ID

11750824

Incident

Jul 1, 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.

NHTSA ID

11744995

Incident

Jun 15, 2026

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

NHTSA ID

11739438

Incident

May 22, 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.

NHTSA ID

11733166

Incident

Apr 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.

NHTSA ID

11733165

Incident

Apr 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.

NHTSA ID

11733164

Incident

Apr 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.

NHTSA ID

11733159

Incident

Apr 21, 2026

Some 2005 – 2026 Toyota vehicles that have undergone water intrusion may exhibit a condition in which a musty odor is present. Follow the procedures in this bulletin to remediate the odor and address this condition. The purpose of this Service Bulletin is to provide general guidelines and procedures for odor remediation. This Service Bulletin provides a guide on how to prepare and treat the interior of the vehicle for odor remediation. Refer to the applicable model and model year Repair Manual and the EPA (Environmental Protection Agency) website for the most up-to-date safety and precautionary guidelines.

The air conditioning dye injection tool kit has been developed to aid in identifying the location of air conditioning refrigerant leaks. The procedures outlined in this Service Bulletin aid in locating, inspecting, and repairing refrigerant leaks.

Acid rain results from rainwater or other airborne moisture that become acidic due to industrial chemical impurities in the atmosphere. If these acidic compounds settle on an exposed vehicle, especially the horizontal areas such as the hood, roof, and decklid, significant damage to the painted surfaces can occur. Acid rain damage can typically be identified on vehicles by the presence of stains on the paint surface that resemble hard water spots. Unlike water spots however, acid rain damage cannot be removed by regular washing procedures. Also, because acid rain can etch and soften the paint, normal buffing or polishing repair procedures should not be attempted. This can cause further damage and result in visible depressions in the paint surface. The following are the three major categories of acid rain damage: •Minor damage: requires only buffing to repair. •Moderate damage: usually requires neutralizing, color sanding, and buffing. •Severe damage: extending beyond 1/2 mil of clearcoat on a pearl, metallic, or solid color, requires neutralization, sanding, and repainting. In cases where acid rain damage is minor, neutralization and buffing with a liquid-type paint finessing product may provide an adequate repair. Only specially formulated products outlined in this bulletin should be used for that purpose. Unfortunately, other than minor damage, there is no simple method of determining the actual extent (depth) of acid penetration other than color sanding a representative affected area until there is no visible etching or depressions, followed by measuring the amount of paint removed with either a magnetic or digital-type film thickness gauge. The procedures in this bulletin are intended for use by qualified body/paint technicians and should not be attempted by inexperienced personnel. It is the dealer’s responsibility to protect and maintain the quality of the vehicle’s paint finish after receipt at the dealership prior to the first sale. Perform frequent vehicle washing, as often as daily, during high heat and humidity periods to minimize the potential for paint damage due to acid rain exposure. This is especially important in geographical areas known for high frequency and concentration of acid rain and industrial fallout.

To prevent brake rotor rust from forming during transportation and storage, wheel film will be used instead of a cardboard type of anti-rust cover. The purpose of the wheel film is to shield the disc brake rotor from weather elements and initial rust before the vehicle is delivered to the customer. Consequently, the film should remain on the wheel for as long as possible.

The condition known as acid rain is caused by airborne chemicals or particles in the atmosphere, which mix with rainwater, nighttime dew, or high humidity to form acidic compounds. If these contaminants settle and remain on a painted vehicle surface, especially the horizonal areas of the hood, roof, and decklid, significant damage can occur. This damage is the result of actual etching of the paint and appears as pitting or water spots. As acid rain droplets on the vehicle surface evaporate, the concentration strength of the acid increases, causing deeper and more rapid damage. This evaporation and corrosive action also occur more rapidly on dark colored cars as direct sun heat increases. It is the dealer’s responsibility to protect and maintain the quality of the vehicle’s paint finish after receipt at the dealership prior to the first sale. In areas known for high frequency and/or concentration of acid rain, frequent vehicle washing during high heat or humidity periods will minimize the potential for paint damage caused by acid rain. It is further recommended that either reverse osmosis or deionized water be used to prevent water spotting.

Toyota vehicles are currently protected with RapgardTM protective film designed to protect the horizontal painted surfaces. This material protects from acid rain, environmental fallout, and rail contamination. Follow the Removal Procedure in this bulletin to remove the RapgardTM protective film within 90 days from initial application.