2021 Toyota Highlander

I had the dealer perform the repair described in Toyota Technical Service Bulletin T-SB-0059-23 (Hybrid Regenerative Brake Transition Feeling Improvement), which reprograms the brake actuator control module. Following this repair, the vehicle continues to exhibit the same lurching behavior at the same frequency as before the update. The TSB did not resolve the underlying condition. This is a safety concern because the unpredictable brake transition affects the driver’s ability to judge stopping distance and vehicle behavior in real time, particularly in traffic or on downgrades. The vehicle now has over 36,000 miles, placing it outside Toyota’s Basic Warranty; however, this is a safety issue that should be addressed by a recall. I am aware of numerous other Highlander Hybrid and Sienna Hybrid owners reporting the same defect, including reports that the same TSB reflash failed to resolve the issue for them as well.

NHTSA ID

11755975

Incident

Aug 10, 2026

This is a formal report of Recall Non-Compliance regarding Safety Recall 23V-720 (Toyota Recall 23TA12) on my 2021 Highlander Hybrid. An authorized dealership performed the recall on May 6, 2024, utilizing Op Code 23TA12R1 (Inspection & Install Fasteners). The dealership only addressed the lower bumper and failed to properly remedy the upper bumper retention tabs, stating it isn’t part of recall. The upper bumper cover has completely separated from the fenders during normal daily driving. The upper plastic mounting slots are torn out and clips will not hold. The dealership is refusing further repairs, instructing me to file a car insurance claim or pay a body shop myself to correct an un-remedied federal safety defect. The vehicle currently remains an active structural road hazard because the official recall remedy completely failed to secure the bumper assembly from detaching. A TAS case has been opened at the dealer, but federal intervention is requested to ensure recall compliance.

NHTSA ID

11755623

Incident

Aug 5, 2024

My transmission started to have a noticeable whine at 53k miles. It became noticeably louder during acceleration. It was diagnosed at the Toyota dealership as a failing transmission. My vehicle was a few months out of warranty. I was told to contact Toyota corporate to ask for assistance. I was told since I did not have a service record at the dealership, they would deny my claim. I advised them the transmission was a sealed unit with no dipstick. My vehicle has been meticulously maintained with records. They said sorry, and the conversation ended.

NHTSA ID

11754750

Incident

Dec 31, 1969

Vehicle is experiencing a distinct, high-pitched mechanical whine or grind sound from the transmission during acceleration that increases in pitch with vehicle speed. The noise does not happen while cruising or coasting. This symptom aligns directly with Toyota Technical Service Bulletin T-SB-0008-21 ('Whine or Grind Noise From Transmission'). I am concerned about a premature, catastrophic internal bearing or gear assembly failure of the UA80 8-speed transmission while driving at highway speeds, which poses a severe sudden loss of propulsion safety risk.

NHTSA ID

11754631

Incident

Apr 6, 2026

High pitched whirring from engine when accelerating. Took to mechanic who diagnosed worn internal transmission bearings that could lead to transmission failure. No warning lights or indicators. Toyota is aware of this issue (see Toyota Technical Service Bulletin T-SB-0008-21) but is doing nothing in response.

NHTSA ID

11754021

Incident

Jul 23, 2026

This vehicle was purchased new in 2021 with 4 original miles. Today it has 58,000 miles and has been maintained, per manufacturer recommendations, a certified Toyota dealership. At around 56,000 miles we noticed a slight whine in first gear. This was attributed to normal noise that we simply had not noticed. by 58,000 miles the while had extended to all gears and become more prominent. Research online shows that this is a known issue with the UH80 transmissions and has been since at least 2017. Toyota has a TSB for it (TSB-0008-21). This was not mentioned at the time of purchase or any of the various maintenance appointments in the last 5 years. This KNOWN issue WILL lead to complete transmission failure. This can happen while parked or in motion and can include the transmission shifting out of an active gear, locking into a gear and being unable to shift to another or park/neutral and there is no way to avoid it. I called Toyota corporate about this because I was not made aware of the TSB until July of 2027 and was advised that, although I was below the 60,000 mile allowance, I had surpassed the 60 month coverage period by two months and would not be granted a warranty exception (Toyota case number: 260710000821). Due to a known defective part on a vehicle that Toyota sold without advisement of said known issue, I am expected to pay $8,000 in repair fee's for a 40,000 dollar car that I have already spent over $20,000 on. The dealership confirmed the issue on 7/28/2026 and are attempting to use my 3rd party warrant which only covers parts. I will still be expected to pay for the labor costs which they expect to land between 2-3k dollars. Toyota is knowingly allowing a defect to persist that puts their customers and anyone else on the road at the time, at risk of serious injury and death. They expect their customers to cover the cost of repairs for an issue that they were aware of at the time of sale

NHTSA ID

11753805

Incident

Jul 28, 2026

On July 25, 2026, while driving my 2021 Toyota Highlander Hybrid at high speeds on the freeway, the vehicle experienced a sudden loss of drive power accompanied by a check engine light and a severe hybrid system error warning. The failure occurred without any prior warning or degradation in performance, forcing an immediate emergency maneuver through traffic to reach the shoulder. The vehicle was towed to Toyota of El Cajon for diagnostic evaluation. The dealership service invoice details the following findings: - Primary Failure: Primary fuel injector failure (direct injection system). - Diagnostic Behavior: The engine experienced severe cylinder misfires under load at freeway speeds when the direct injectors were commanded on. - System Impact: Engine misfires triggered a hard safety shutdown of the hybrid system, immediately cutting motive power to the wheels. - Repair Executed: Replacement of the failed fuel injector assembly Safety Concern: A primary fuel injector failure at highway speeds causes an instantaneous engine misfire under load, which immediately triggers a hard hybrid drive system shutdown. Cutting motive power suddenly in heavy traffic without advance warning creates an extreme hazard for rear-end collisions. I am requesting NHTSA document and investigate this failure mode and its automated system shutdown logic.

NHTSA ID

11753720

Incident

Jul 25, 2026

The contact owns a 2021 Toyota Highlander. The contact stated that while driving 25 MPH, there was an abnormal whining sound coming from the engine. The vehicle was taken to the dealer, where it was diagnosed with transmission failure due to a pinion shaft failure. The dealer determined that the transmission needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 62,300.

NHTSA ID

11753484

Incident

Jun 29, 2026

Mileage

62,300 mi

Some 2020 – 2026 model year Highlander and Highlander Hybrid vehicles may exhibit a water leak from the roof rack attachment clips. This may be caused by the sealant in the roof channel obstructing the proper seating position for the clip gasket.

Some 2020 – 2024 model year Highlander and Highlander Hybrid vehicles may exhibit a condition in which the air conditioner does not cool due to a leak and/or corrosion in the rear underbody air conditioner tube and accessory assembly. The anti-corrosion material has been updated to reduce the possibility of this condition.

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 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 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 2020 – 2023 model year Highlander and Highlander Hybrid vehicles may exhibit a condition in which the Power Back Door (PBD) will not open or close and/or stops moving while opening or closing. A modified PBD unit assembly is available to address these conditions.