AI Damage2018 Toyota Sienna: common problems
Owners of the 2018 Toyota Sienna filed 72 complaints with NHTSA, most often about powertrain and fuel/propulsion system. The maker issued 155 service bulletins for this year. Details by component below, with sources.
Key figures
- Owner complaints
- 72
- involving a crash
- 5
- Technical service bulletins (TSB)
- 155
What fails most often
- 1 Powertrain 28% of all complaints
- 2 Fuel/propulsion system 13% of all complaints
- 3 Electrical system 10% of all complaints
- 4 Structure 7% of all complaints
- 5 Engine 7% of all complaints
- 6 Air bags 7% of all complaints
- 7 Vehicle speed control 7% of all complaints
- 8 Fuel system 6% of all complaints
- Powertrain: 20 complaints (28% of all); manufacturer bulletins for this component: 3.
- Fuel/propulsion system: 9 complaints (13% of all).
- Electrical system: 7 complaints (10% of all); manufacturer bulletins for this component: 40.
- Structure: 5 complaints (7% of all); manufacturer bulletins for this component: 28.
- Engine: 5 complaints (7% of all); manufacturer bulletins for this component: 7.
Engines and transmissions
US-market versions per EPA. On the right: how many NHTSA complaints name this engine or transmission type.
- 3.5 L · petrol · 6 cyl
- automatic, 8-speed
Drive: FWD, AWD
Symptoms owners describe
How many of the 72 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Powertrain | 20 | 0 | 3 |
| Fuel/propulsion system | 9 | 0 | 0 |
| Electrical system | 7 | 0 | 40 |
| Structure | 5 | 0 | 28 |
| Engine | 5 | 0 | 7 |
| Air bags | 5 | 4 | 4 |
| Vehicle speed control | 5 | 1 | 2 |
| Fuel system | 4 | 0 | 3 |
| Seats | 4 | 0 | 2 |
| Service brakes | 2 | 0 | 7 |
| Visibility | 2 | 0 | 4 |
| Equipment | 1 | 0 | 60 |
| Wheels | 1 | 0 | 2 |
| Tires | 1 | 0 | 1 |
What owners report
Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.
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 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.
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.
Unintended acceleration while reversing vehicle. Van went full throttle and sped up in reverse while backing up from my drive way at home.
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)
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.
The vehicle has developed a pronounced whining noise from the transmission that rises with road speed, accompanied by harsh/rough shifting. [dealer] dealer inspected the vehicle and diagnosed a failing transmission requiring replacement.
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.
When owners complained
NHTSA complaints by filing year. The peak shows at what age the problems show up most.
Comparison
By complaint count this model year ranks 722 of 2,102 model years in the NHTSA data (top 34% most complained about).
On average one model year of the Sienna has 77 complaints (5 years in the data). This year has 72, about average.
What to check before buying
- Powertrain. Shift quality under load, harsh shifts, transmission codes, CV joints.
- Fuel/propulsion system. Fuel smell, leaks, rough running, fuel-system codes.
- Electrical system. Scan all modules, test the battery and alternator, inspect connectors near the impact zone.
- Structure. Rails, pillars, panel gaps, signs of pulling or welding.
Manufacturer service bulletins
Bulletin titles as filed with NHTSA.
- OBSOLETE NOTICE January 30, 2026
This bulletin is now obsolete. Please see T-SB-0001-26.
- Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System…
Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System require a Special Service Tool (SST) USB flash drive to update the map, points of interest, and system software.
- Some 2005 – 2026 Toyota vehicles that have undergone water intrusion may exhibit a condition in which a…
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…
- 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…
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…
- To assist with the early detection and early resolution of audio related concerns you may be asked to…
To assist with the early detection and early resolution of audio related concerns you may be asked to recover MMR data from the head unit. The following steps are instructions on how to retrieve the data from the…
- Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System…
Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System require a Special Service Tool (SST) USB flash drive to update the map, points of interest, and system software…
- The condition known as acid rain is caused by airborne chemicals or particles in the atmosphere, which mix…
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…
- To prevent brake rotor rust from forming during transportation and storage, wheel film will be used…
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…
- Acid rain results from rainwater or other airborne moisture that become acidic due to industrial chemical…
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…
- Toyota vehicles are currently protected with RapgardTM protective film designed to protect the horizontal…
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…
- Vehicles may occasionally be subjected to contamination by airborne iron particles shed from railroad…
Vehicles may occasionally be subjected to contamination by airborne iron particles shed from railroad tracks, train wheels, exposure to heavy machinery facilities, grinding, welding, etc. This type of contamination can…
NHTSA lists 155 bulletins for this year; the 12 newest are shown here.
Other years of this model
Questions and answers
What are the most common problems with the 2018 Toyota Sienna?
Owner complaints to NHTSA most often mention: powertrain, fuel/propulsion system, electrical system. Total complaints: 72. The most frequent symptoms in complaint texts: knocking, grinding or other noise (13%), hesitation when accelerating (11%), warning lights, check engine (11%).
How many service bulletins (TSB) were issued for the 2018 Toyota Sienna?
NHTSA lists 155 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.
Should I buy a 2018 Toyota Sienna from a US auction?
Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.
Other 2018 models
Read also
Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-04.