TT: Some 2014-2021 model year vehicles equipped with Dynamic Torque Control AWD system may experience a ?Noise? or ?Abnormal Operation? condition from the rear differential front coupling. In some cases, even an ?AWD System Message? with or without a DTC may be present with or without other conditions present.
full bulletin at NHTSA ↗2015 Toyota Sienna powertrain problems
severe Owners of the 2015 Toyota Sienna have filed 10 NHTSA complaints about the powertrain at roughly $2,500 to repair (U.S. federal records, as of August 2026). Source: NHTSA Office of Defects Investigation. See powertrain across all vehicles →
Complaints
10
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2011 Sienna | 28 |
| 2012 Sienna | 16 |
| 2013 Sienna | 14 |
| 2014 Sienna | 6 |
| 2015 Sienna (this page) | 10 |
| 2016 Sienna | 3 |
| 2017 Sienna | 34 |
| 2018 Sienna | 18 |
| 2019 Sienna | 7 |
2crashes
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
TSB: REVISION NOTICE July 01, 2019 Rev2: ? Applicability has been updated to 2019 ? 2020 model year Toyota vehicles. ? The Techstream Preparation and Process Overview sections have been updated. October 30, 2017 Rev1: ? Applicability has been updated to include 2018 model year vehicles. Any previous printed versions of this bulletin should be discarded. SUPERSESSION NOTICE The information contained in this bulletin supersedes SB No. T-SB-0012-13. Service Bulletin No. T-SB-0012-13 is obsolete and any printed versions should be discarded. Be sure to review the entire content of this bulletin before proceeding. Flash reprogramming allows the Electronic Control Unit (ECU) software to be updated
full bulletin at NHTSA ↗TSB: This bulletin includes basic procedures for inspecting and adjusting World Standard (WS) Automatic Transmission Fluid (ATF) level at normal vehicle operating temperature. Note: The following adjustment procedures are for U660E/F and U760E/F transmissions.
full bulletin at NHTSA ↗TSB: World Standard (WS) Automatic Transmission Fluid (ATF) was introduced to reduce maintenance costs and increase the mileage between scheduled maintenance checks. Here are some important tips when working with ATF-WS in Toyota vehicles requiring it's use.
full bulletin at NHTSA ↗TSB: The purpose of this bulletin is to provide precautions to follow when installing an automatic transmission/transaxle assembly to avoid MIL "ON" shifting issues and/or transmission damage. Use the information in this bulletin when installing an automatic transmission/transaxle assembly.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The dominant complaint is the shift lever unexpectedly dropping out of Park while the vehicle sits parked, with the engine off and no keys in the ignition. Multiple owners describe their Siennas rolling away from the driveway or parking lot, hitting houses, fire trucks, and other property. This happens with the brake pedal unpressed and occurs despite Toyota's dealership inspection finding no fault and the manufacturer declining responsibility. One owner notes Toyota has issued recalls for the same defect on earlier model years, raising questions about why the 2015 model wasn't included.
A second distinct issue: one owner's shifter got stuck in Park and wouldn't come out; the engine wouldn't restart and a brake override malfunction code lit up the dash.
Owners also report transmission problems, including failure at 7,000 miles following a minor crash, and delayed throttle response—the pedal requires heavy foot pressure and takes several seconds to produce engine response, creating highway merge hazards.
Cold-start behavior in freezing temperatures produces rough idle with the engine revving 500 RPM higher than normal during downshifts and stop-and-go, causing the van to lurch forward; a dealer told one owner this was normal.
Same Toyota Sienna powertrain reports on nearby years: 2012 · 2013 · 2017 · 2018
Failure modes owners describe
Shifter falls out of Park without key or ignition on
Shift lever unexpectedly disengages from Park position and vehicle enters Drive, allowing vehicle to roll without ignition on, keys in vehicle, or brake pedal pressed. Multiple owners report shift lever dropping out of Park while parked in driveway or parking lot, resulting in uncontrolled roll and collisions.
When: While parked; one incident at 119,274 miles; another owner mentions purchase was recent
Symptoms owners cite: Shift lever falls out of Park into Drive; Vehicle rolls away while parked; Occurs with ignition off and no keys in vehicle; Occurs without brake pedal pressed; Vehicle collision into property or other vehicles
Repairs/costs cited: Local dealer inspection did not identify or diagnose the failure; manufacturer declined claim in at least one case
Recalls/TSBs owners mention: Toyota inspection stated no evidence of gear shift operation concern; Toyota claims no responsibility; owner notes active recalls exist on earlier model years for same issue
Shift lever stuck in Park with no restart
Gear stuck in Park position after owner places vehicle in Park. Vehicle will not restart and brake override malfunction indicator illuminates with 'Visit Your Dealer' warning.
When: At 72,043 miles
Symptoms owners cite: Unable to shift out of Park position; Vehicle will not restart after shutdown; Brake override malfunction indicator illuminated; 'Visit Your Dealer' message appears on instrument panel
Codes mentioned: Brake override malfunction indicator
Repairs/costs cited: Vehicle towed to dealer for diagnosis; results pending at time of report; not repaired
Transmission failure after minor crash
Transmission fails and requires replacement following a minor crash. Vehicle exhibits abnormal driving sensation described as transmission failing.
When: At approximately 7,000 miles
Symptoms owners cite: Vehicle not driving normally; Sensation of transmission failing; Transmission failure requiring replacement
Repairs/costs cited: Dealership diagnosed transmission failure; transmission was replaced
Recalls/TSBs owners mention: Manufacturer was informed of failure
Delayed throttle response on acceleration
Acceleration response is very delayed, particularly problematic during highway merging. Accelerator pedal requires hard pressing; engine does not respond for several seconds then suddenly accelerates without proportional input.
When: Ongoing for several months; no mileage specified
Symptoms owners cite: Very late response to acceleration; Acceleration pedal must be pressed very hard; No engine response for first few seconds; Sudden acceleration after delay; Particularly problematic during highway merging; Creates safety hazard for misjudging merge timing
Cold start rough idle and lurching
Engine revs excessively during cold starts and downshifting in freezing temperatures. Engine revs from below 1000 RPM to nearly 1500 RPM when coming to a stop with vehicle attempting to lurch forward. Owner reports needing to maintain brake pressure to prevent lurching.
When: When ambient temperature is below freezing and vehicle is cold
Symptoms owners cite: Engine revs from below 1000 RPM to nearly 1500 RPM during stop; Vehicle wants to lurch forward; Lurching occurs as transmission downshifts; Occurs in cold/freezing ambient temperatures
Recalls/TSBs owners mention: Dealer stated this is normal operation
Synthesized from 10 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 0 most recent
Had powertrain trouble with your 2015 Toyota Sienna?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2015 Toyota Sienna?
It's a meaningful issue. 10 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $2,500.
At what mileage does the powertrain typically fail?
Based on the 10 complaints filed, powertrain issues most often appear around 52,863 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2015/Toyota/Sienna.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.