2017 Toyota Sienna

I, as well as other owners of 2017–2018 Toyota Highlanders and 2017–2018 Siennas are experiencing serious transmission issues—including high-pitched whining, erratic shifting, clunks, hesitation, and premature failure. My 2017 Toyota Sienna has the UA80 8-speed automatic transmission at issue and started whining upon acceleration in March/April 2026 timeframe. It has always had the clunking and hesitation problem. According to Gears Magazine, the issue stems from a flawed assembly process involving the counter drive gear support. A locking tab meant to secure a vital retaining nut was not bent properly during factory assembly. This leads to gear movement, internal wear, whining, and eventually failure. Unknown to me, in 2019, Toyota had acknowledged the problem in Technical Service Bulletins T-SB-0160-18, T-SB-0008-21, which only go to dealers, and implemented a limited Customer Support Program (CSP ZJC)—but only offered coverage to a narrow group of VINs, not to all VINs for model years that have these transmissions. My car is experiencing these same symptoms. My Toyota Dealer confirmed this problem and recommended a transmission replacement for $11,000 including labor. They said my VIN was not included in the Customer Support Program. Driving with a failing transmission is highly dangerous. A bad transmission can cause sudden power loss causing the car to halt to a sudden stop, unintended acceleration, or my car might get stuck in neutral while driving. I could lose control or be unable to get to the shoulder on the highway, cause a rear-end collision, or get stuck in busy traffic. DESIRED OUTCOME REQUEST: My VIN should be covered under the Customer Support Program in the category of cars that are “less than 10 years old regardless of mileage” or a full recall of all VINs of these model years with these transmissions should be executed. Thank you.

NHTSA ID

11749682

Incident

Apr 1, 2026

power sliding door (behind front passenger) does not fully engage arresting hook and tends to immediately return to open position and after hitting the button again starts welling. It started about eight months ago. Now it isn’t connected at all, I just open or close it and it slides but don’t try to open it first if it’s locked or the alarm blares. I may have pulled or pushed it too many times trying to open or close it so I could drive the car. Looks like others have had the same issue with their driver side passenger door too.

NHTSA ID

11748961

Incident

Oct 17, 2025

I have a 2017 Toyota Sienna XLE with about 120k miles on it. Out of nowhere the transmission was gear hunting and surging. It eventually became impossible to get it above 30 mph. It seemed like the transmission just went haywire. No lights on the dash let me know anything was wrong. Thankfully I had just pulled off the highway. Otherwise it could've been bad. I couldn't drive it safely so I had it towed to the nearest Toyota dealership. They said that the transmission needed to be replaced. $9k....

NHTSA ID

11746069

Incident

Jun 22, 2026

While driving at speed, the vehicle suffered a sudden and complete loss of engine power and stalled in traffic. The vehicle was diagnosed by an independent mechanic who found a failed factory-installed Denso fuel pump module. This failure mirrors Toyota Safety Recall 20TA02 (NHTSA Campaign 20V012) for the exact same model year 2017 Toyota Sienna, but my specific VIN is currently excluded from the recall list. The un-recalled defective component created an immediate highway safety hazard as me and my family were left stranded in the middle of the road. We waited for hours at the risk of oncoming traffic until we were able to have a tow truck lift the van and take to the nearest repair facility (an independent service center - Goodyear Auto Service). The repair facility diagnosed the problem and confirmed that the fuel pump failed to generate enough pressure causing the vehicle to stall and not start again. To correct the problem, the fuel pump was replaced with an OEM toyota fuel pump module assembly.

NHTSA ID

11745697

Incident

Sep 7, 2024

We experienced a high whine for a couple of months. No codes were being read by any mechanics. Then the transmission started slipping between 2nd and 3rd gears, and then we couldn’t reverse. Now it’s not switching gears at all. There is a recall for our year and type of transmission, for this issue, but our vin number is not included in that recall.

NHTSA ID

11742281

Incident

Mar 4, 2026

I have a 2017 Sienna AWD with a UA80 Transmission and the Check AWD System light appeared. I was able to drive it to Towne Toyota in Ledgewood, NJ and they detected the Sienna having DTC Codes P07407E, P27137F and P27567F. They they recommended a transmission replacement costing $9260.84 before tax that I can't afford right now. I am still able to drive the Sienna but Towne Toyota said that the Transmission will eventually fail. After some research, I discovered there is "ZJC UA80 Warranty_Enhancement" by Toyota. I am troubled that the service folks in Towne Toyota did not make me aware of this program! I am afraid to drive the vehicle knowing that the Check Engine Light may reappear. Or worse, the transmission can completely fail unexpectedly that may prevent me or other vehicles from avoiding a collision. It could also strand me on a busy highway and can possibly put my family at risk.

NHTSA ID

11739882

Incident

May 12, 2026

The transmission went out. It wouldn't shift going 45-55 mph. We stopped at a light and put it into Park, then put it into drive but it wouldn't go. We were stuck at a light in traffic 10:30pm. We had to call 911 to get a cop to sit behind us so we wouldn't get hit. My wife, my 3 kids, and I were in the minivan. While waiting for the tow truck I saw on reddit that many 2017/2018 Toyota Sienna's had transmission problems. The vehicle is at Milton Martin toyota in Gainesville, GA. Toyota says it isn't covered by Bulletin ZJC. Toyota said the transmission is the issue.

NHTSA ID

11739526

Incident

May 16, 2026

Transmission is making a winning sound. Toyota had issued a Customer Support Program (Program ZJC/POL19-04) for some of that year but it seems to affect more than what they have allowed

NHTSA ID

11738660

Incident

Mar 31, 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.

Some customers may experience echoing on the line calling the vehicle when using Bluetooth Hands Free. This is caused by the phone Hands Free volume being too low.

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.