2017 Toyota Sienna Complaints

POWER TRAIN — Filed 04/01/2026

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.

ELECTRICAL SYSTEM — Filed 10/17/2025

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.

POWER TRAIN — Filed 06/22/2026

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....

FUEL/PROPULSION SYSTEM — Filed 09/07/2024

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.

POWER TRAIN — Filed 03/04/2026

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.

POWER TRAIN — Filed 05/12/2026

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.

POWER TRAIN — Filed 05/16/2026

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.

POWER TRAIN — Filed 03/31/2026

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

POWER TRAIN — Filed 02/02/2026

I am writing to report a safety defect regarding the 8-speed automatic transmission in my 2017 Toyota Sienna. The vehicle exhibits severe hesitation during acceleration, harsh shifting, and a high-pitched whining noise, specifically consistent with the 'whine of death' described in Toyota's Customer Support Program ZJC and related Technical Service Bulletin T-SB-0160-18.Despite these identical symptoms, my vehicle’s VIN is not included in the coverage list. This hesitation during acceleration creates a serious safety issue, as the car fails to accelerate unexpectedly when attempting to merge or cross traffic. My vehicle is equipped with the UA80F/E transmission, which is documented to have a faulty assembly (improperly bent washer tab). I request that NHTSA investigate the exclusion of my VIN from this program, as the defect poses a significant risk to passenger safety and the safety of others on the road.

POWER TRAIN — Filed 04/10/2026

Loss of power highway speeds, jerky shifting, “sealed” transmission leaking fluid. Check engine light and service required light. I have noticed poor performance with this vehicle before and reported it to the dealer to no avail. Toyota has enacted “customer support program ZJC” but the dealership will not honor.