AutoUtility currently tracks 69 official NHTSA owner defect complaints for the 2018 Toyota Sienna. Powertrain & Transmission issues are the most frequently reported category, appearing in 18 complaints (26.1% of submitted records). Among these NHTSA complaint records, 5 filings cite a crash, 3 report one or more injuries.

Key Problem Findings
  • Total NHTSA Complaints: 69 reports
  • #1 Reported Problem Area: Powertrain & Transmission (18 reports • 26.1% of submitted complaints)
  • Secondary Problem Areas: Fuel & Propulsion System (13), Electrical System (6)
  • Crash-Citing Complaints: 5 filings
  • Fire-Citing Complaints: 0 filings
  • Complaints Reporting Injuries / Fatalities: 3 injury filings • 0 fatality filings
Reporting Methodology: Statistics describe unverified consumer submissions voluntarily filed with NHTSA. Complaint volume is not normalized for vehicle sales volume or miles driven. Multiple components can be cited within a single owner complaint submission.
Total Complaints
69
Submitted to NHTSA ODI
Crash-Citing Complaints
5
Filings citing a collision
Fire-Citing Complaints
0
Filings citing smoke or fire
Complaints Reporting Injuries
3
Filings citing one or more injuries
Complaints Reporting Fatalities
0
Consumer filings citing fatalities

Most Reported Problems for 2018 Toyota Sienna

Top automotive subsystem defect categories ranked by unique owner complaint volume in federal records

#1 Problem Area 26.1% of complaints

Powertrain & Transmission

18 owner complaints submitted to NHTSA ODI
✓ 0 crashes or fires cited
#2 Problem Area 18.8% of complaints

Fuel & Propulsion System

13 owner complaints submitted to NHTSA ODI
⚠️ NHTSA Recall Context

NHTSA records list 2 official safety recall campaigns for this model year involving the same broad component area:

*Component overlap means an official recall exists for the same broad vehicle system. It does not establish that an individual owner complaint was caused by, covered by, or resolved through that recall.
✓ 0 crashes or fires cited
#3 Problem Area 8.7% of complaints

Electrical System

6 owner complaints submitted to NHTSA ODI
✓ 0 crashes or fires cited
#4 Problem Area 8.7% of complaints

Air Bags & Restraints

6 owner complaints submitted to NHTSA ODI
⚠️ 4 crash reports 🩹 5 injury report entries
#5 Problem Area 7.2% of complaints

Body & Structure

5 owner complaints submitted to NHTSA ODI
✓ 0 crashes or fires cited
Domain Share Note: Share percentage represents the proportion of unique complaint filings referencing each vehicle system. Because single complaints may cite multiple systems (such as engine and electrical simultaneously), domain percentages represent individual category incidence and may sum to over 100%.

Recent NHTSA Owner Reports for 2018 Toyota Sienna

Representative defect filings submitted by owners to the NHTSA Office of Defects Investigation

Powertrain & Transmission NHTSA ODI ID: #11750202
Filed: 07/14/2026

"Vehicle: 2018 Toyota Sienna XLE AWD, VIN [XXX], approximately 112,000 miles. Component: Power Train / Automatic Transmission (UA80F 8-speed). The vehicle has developed a pronounced whining noise from the transmission that rises with road speed, accompanied by harsh/rough shifting. A Toyota dealer..."

Incident Date: 06/01/2026 • Raw NHTSA Component: POWER TRAIN
Powertrain & Transmission NHTSA ODI ID: #11745443
Filed: 06/21/2026

"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. The problem is a safety issue as..."

Incident Date: 06/04/2026 • Raw NHTSA Component: POWER TRAIN
Powertrain & Transmission NHTSA ODI ID: #11719964
Filed: 02/23/2026

"My 2018 Sienna had developed a whining noise when accelerating. After taking it in to the mechanic, they advised the transmission was failing. Estimated price tag of $6500-7000 to repair. The vehicle has less than 140K miles. Looking at different issues with this make/model and year, it seems like..."

Incident Date: 02/01/2026 • Raw NHTSA Component: POWER TRAIN
Powertrain & Transmission NHTSA ODI ID: #11715126
Filed: 02/02/2026

"The contact owns a 2018 Toyota Sienna. The contact stated that while driving 30 MPH and ascending a hill, the vehicle started making an abnormal whining sound and hesitated while accelerating. The vehicle was driven to the dealer to be diagnosed. The vehicle was diagnosed with transmission failure...."

Incident Date: 11/01/2025 • Raw NHTSA Component: POWER TRAIN
Powertrain & Transmission NHTSA ODI ID: #11711540
Filed: 01/16/2026

"Transmission has been whining. A P27137F Code appeared and the vehicle is only in 2WD mode currently. Concerned to drive vehicle due to further damaging transmission or getting stuck while on the road."

Incident Date: 01/14/2026 • Raw NHTSA Component: POWER TRAIN
Consumer Narrative Notice: Excerpts are sanitized text descriptions submitted by vehicle owners to the federal ODI database. They reflect the reporting consumer's observations at the time of filing and have not been independently confirmed by vehicle manufacturers or government investigators.

Complaint History for Toyota Sienna

Reported defect complaint volume across sibling model years (2015–2026)

Model Year NHTSA Complaints Crash Reports Safety Recalls Detailed Report
2015 Toyota Sienna 230 17 6 View 2015 Problems →
2016 Toyota Sienna 75 7 5 View 2016 Problems →
2017 Toyota Sienna 152 13 10 View 2017 Problems →
2018 Toyota Sienna Current Page 69 5 7 Current
2019 Toyota Sienna 45 2 7 View 2019 Problems →
2020 Toyota Sienna 37 0 2 View 2020 Problems →
2021 Toyota Sienna 37 0 4 View 2021 Problems →
2022 Toyota Sienna 15 1 4 View 2022 Problems →
2023 Toyota Sienna 66 8 2 View 2023 Problems →
2024 Toyota Sienna 65 5 3 View 2024 Problems →
2025 Toyota Sienna 264 2 5 View 2025 Problems →
2026 Toyota Sienna 0 0 0 View 2026 Problems →
Comparative Disclaimer: Complaint totals are unadjusted historical counts and are not normalized for vehicles sold, active fleet size, or total road mileage. Newer model years naturally have had less calendar exposure time to accumulate owner filings.

Detailed NHTSA Component Breakdown for 2018 Toyota Sienna

Complete distribution of consumer defect reports across all 29 granular NHTSA system and subsystem classifications

Vehicle Component / System Total Complaints Crash Reports Fire Reports Reported Injury Entries Reported Fatality Entries
Powertrain NHTSA category: POWER TRAIN 13 0 0 0 0
Other / Uncategorized NHTSA category: UNKNOWN OR OTHER 10 0 0 1 0
Fuel & Propulsion System NHTSA category: FUEL/PROPULSION SYSTEM 7 0 0 0 0
Air Bags NHTSA category: AIR BAGS 4 4 0 5 0
Fuel System NHTSA category: FUEL SYSTEM, GASOLINE 4 0 0 0 0
Electrical System NHTSA category: ELECTRICAL SYSTEM 3 0 0 0 0
Structure & Body NHTSA category: STRUCTURE 3 0 0 0 0
Engine NHTSA category: ENGINE 2 0 0 0 0
POWER TRAIN,VEHICLE SPEED CONTROL 2 0 0 0 0
Seats & Restraints NHTSA category: SEATS 2 0 0 0 0
CHILD SEAT 1 0 0 0 0
ELECTRICAL SYSTEM,AIR BAGS,ENGINE 1 0 0 0 0
ELECTRICAL SYSTEM,SEATS 1 0 0 0 0
ELECTRICAL SYSTEM,UNKNOWN OR OTHER 1 0 0 0 0
EQUIPMENT ADAPTIVE/MOBILITY 1 0 0 0 0
EXTERIOR LIGHTING,INTERIOR LIGHTING 1 0 0 0 0
POWER TRAIN,ENGINE 1 0 0 0 0
POWER TRAIN,STRUCTURE,SEATS 1 0 0 0 0
POWER TRAIN,VEHICLE SPEED CONTROL,SERVICE BRAKES 1 0 0 0 0
Service Brakes NHTSA category: SERVICE BRAKES 1 0 0 0 0
STRUCTURE,UNKNOWN OR OTHER 1 0 0 0 0
Suspension NHTSA category: SUSPENSION 1 0 0 0 0
Tires NHTSA category: TIRES 1 0 0 0 0
UNKNOWN OR OTHER,ENGINE,FUEL/PROPULSION SYSTEM 1 0 0 0 0
Vehicle Speed Control NHTSA category: VEHICLE SPEED CONTROL 1 1 0 0 0
VEHICLE SPEED CONTROL,FUEL/PROPULSION SYSTEM 1 0 0 0 0
Visibility / Glass NHTSA category: VISIBILITY 1 0 0 0 0
Visibility & Wipers NHTSA category: VISIBILITY/WIPER 1 0 0 0 0
Wheels & Hubs NHTSA category: WHEELS 1 0 0 0 0
Data Attribution & Reporting Methodology: Complaints are unverified voluntary submissions to the NHTSA Office of Defects Investigation (ODI). Because multiple vehicle components can be cited within a single owner complaint submission, component-level rollups may sum to more than the unique complaint count (69). Injury and fatality entries in the detailed table reflect raw values entered by reporting consumers across individual submissions; they are not deduplicated casualty statistics and may include duplicate or unverified entries. Complaint volume is not normalized for sales volume or vehicle mileage and does not represent an audited component failure rate.
Official US Government Data Provenance

The complaint records on this page are retrieved directly from the NHTSA Office of Defects Investigation (ODI) public database.

Local Production Store Compiled: August 2026 • Deterministic Audited Dataset • Zero Dynamic External API Runtime Latency.