FaultScore

2021 Toyota Highlander driver assist problems

33 of the 618 complaints about the 2021 Toyota Highlander are about the driver-assist systems — 5% of everything reported for this model year. Half of the failures with a mileage on record happened before 5,000 miles.

C

33

Complaints

4

Crashes

0

Fires

2

Injuries

Exactly what failed

Automatic Emergency Braking 9 27.3%
Warnings 5 15.2%
Assist 4 12.1%
Blind Spot Detection 3 9.1%
Adaptive Cruise Control 3 9.1%
Warnings 3 9.1%
Warning 2 6.1%
Automatic Steering 1 3.0%
Display Function 1 3.0%
Steering Assist 1 3.0%

Driver Assist & Collision Avoidance across every Toyota Highlander year

2018 17 13.7%
2019 16 12.9%
2020 12 9.7%
2021 33 26.6%
2022 33 26.6%
2023 13 10.5%

What owners said

Filed with NHTSA, in their own words.

Yuma, AZ

FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL

2021 Toyota Highlander UA80 transmission failed at 100,000 miles. Codes P2808, P0741. Matches Toyota TSB-0160-18 and T-SB-0008-21. Dealer Alexander Toyota and TMS Brand Engagement denied goodwill. TMS rep stated "TSBs don't matter" despite pending class action Pallaya v Toyota, Case 2:25-cv-10458, which cites these TSBs as proof Toyota knew of defect. Toyota refusing to honor documented defect. Transmission slip/loss of power is safety issue. Request investigation.

NHTSA complaint #11746525 — an unverified report by a vehicle owner.

Yuma, AZ

FORWARD COLLISION AVOIDANCE: WARNINGS

2021 Toyota Highlander UA80 transmission failed at 100,000 miles. Codes P2808, P0741. Matches Toyota TSB-0160-18 and T-SB-0008-21. Dealer Alexander Toyota and TMS Brand Engagement denied goodwill. TMS rep stated "TSBs don't matter" despite pending class action Pallaya v Toyota, Case 2:25-cv-10458, which cites these TSBs as proof Toyota knew of defect. Toyota refusing to honor documented defect. Transmission slip/loss of power is safety issue. Request investigation.

NHTSA complaint #11746525 — an unverified report by a vehicle owner.

Yuma, AZ

LANE DEPARTURE: ASSIST

2021 Toyota Highlander UA80 transmission failed at 100,000 miles. Codes P2808, P0741. Matches Toyota TSB-0160-18 and T-SB-0008-21. Dealer Alexander Toyota and TMS Brand Engagement denied goodwill. TMS rep stated "TSBs don't matter" despite pending class action Pallaya v Toyota, Case 2:25-cv-10458, which cites these TSBs as proof Toyota knew of defect. Toyota refusing to honor documented defect. Transmission slip/loss of power is safety issue. Request investigation.

NHTSA complaint #11746525 — an unverified report by a vehicle owner.

Raleigh, NC

LANE DEPARTURE: BLIND SPOT DETECTION

Four days after I took delivery of this used vehicle (April 25, 2026), multiple warning lights appeared at once: BRAKE, ABS, PARK, Check Engine, Blind Spot Monitor Unavailable, and RCTA OFF. An independent Toyota dealership diagnosed the vehicle April 27-28, 2026 (approx. 109,000 miles) and found (1) water leaking into the rear hybrid battery area through a sunroof drain "installed incorrectly," causing a Brake System Control Module low-voltage code, starting issues, a headlight only partially functioning on one side, possible air in the brake system, and a musty HVAC odor; and (2) blind spot monitor fault code C1AC2 (Slave Module Horizontal Axis Misalignment) - the blind spot and rear cross-traffic monitoring systems do not function reliably. At a second visit on May 4, 2026, recalibration was unsuccessful; per Toyota procedure the only remaining option is replacing the right-rear blind spot sensor. The technician wrote the cause is a mystery, "whether it be body damage related or electrical short." Toyota service records show the same C1AC2 code was documented during the selling dealer's own pre-sale inspection, and that in December 2024 another Toyota dealership pulled the rear bumper and found the RR blind spot sensor bracket bent, causing incorrect readings - a recurring safety defect that prior calibrations and repairs have not resolved. Separately, federal safety recall 23V865 (occupant classification sensors; the passenger airbag may not deploy as designed) was open and incomplete when I purchased the vehicle and remains incomplete, and Toyota service campaign 25TD01 (rear traction motor cable corrosion) is also outstanding. The defect has been reproduced and confirmed by two Toyota dealerships, reported to the selling dealer in writing, and reported to Toyota's customer-care center. The vehicle is available for inspection upon request. No crash, fire, or injury.

NHTSA complaint #11743384 — an unverified report by a vehicle owner.

Henrico, VA

BACK OVER PREVENTION: WARNINGS

The parking sensor bracket has failed twice now and the sensor keeps falling through. There are no signs of scratches or bumps on the bumper. The dealer said that’s not something they will fix. I have had it fixed once before and now it’s happening again.

NHTSA complaint #11738736 — an unverified report by a vehicle owner.

Apalachicola, FL

BACK OVER PREVENTION: WARNINGS

The vehicle experiences intermittent power steering malfunction while driving. Warning messages including “Power Steering Malfunction” and “Low Voltage Abnormality” appear, and the steering wheel becomes stiff and difficult to turn. This has occurred multiple times during normal driving conditions, including at low speeds and while turning. When the issue occurs, it requires increased effort to steer, creating a risk of loss of control. Additional warning messages have included AWD malfunction, pre-collision system malfunction, and lane tracing assist malfunction. These alerts appear simultaneously with the steering issue. The problem began shortly after purchase and has continued intermittently. The vehicle has been inspected, but the issue has not been resolved. This condition creates a safety risk, especially when driving with passengers.

NHTSA complaint #11728216 — an unverified report by a vehicle owner.

at 45,000 miles Newton, NH

BACK OVER PREVENTION:DISPLAY FUNCTION

The contact owns a 2021 Toyota Highlander. The contact stated that while operating the vehicle, the display screen malfunctioned and displayed a solid black screen. During the failure, several functions and features could not be accessed or activated, including the front and rear defrosters. The contact was unable to clear the front and rear windshields, which created a visibility hazard for the driver. The vehicle was taken to the local dealer, who diagnosed that the display screen unit needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure, but no assistance was offered. The failure mileage was 45,000.

NHTSA complaint #11649388 — an unverified report by a vehicle owner.

Ocean City, NJ

FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL

Subject: Transmission Issue – 2021 Toyota Highlander Dear NHTSA, I am reporting a serious transmission issue with my 2021 Toyota Highlander (82,000 miles). I recently took it to the dealership for an unusual noise, and they diagnosed a transmission failure, quoting over $9,000 for replacement and service. After researching, I discovered Toyota has known about transmission issues in the 2021 Highlander since at least 2021. I have always serviced my vehicle at the same dealership, yet they never informed me of this known defect. Instead, they waited until my warranty expired to disclose the issue, despite my repeated maintenance visits where I reported the noise. I also found a 2021 Toyota document acknowledging transmission problems in this model, and many other owners have reported the same issue. It seems dealerships avoided addressing this until warranties expired, leaving owners with massive repair costs. This raises serious concerns about Toyota’s handling of known defects. I urge the NHTSA to investigate and take action to protect consumers from unfair repair costs and potential safety risks.

NHTSA complaint #11639473 — an unverified report by a vehicle owner.

Carson, CA

FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING

The Battery was leaking fluid, smoke was visible and rotten smell from the battery. Electrical secondary brake system came on the dashboard

NHTSA complaint #11626440 — an unverified report by a vehicle owner.

Tucson, AZ Crash 1 injured

FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING

Unknown

NHTSA complaint #11608965 — an unverified report by a vehicle owner.

Tucson, AZ Crash 1 injured

FORWARD COLLISION AVOIDANCE: WARNINGS

Unknown

NHTSA complaint #11608965 — an unverified report by a vehicle owner.

Humble, TX

FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING

The start/stop operating system failed. When the engine cut off while waiting for train to pass, the engine went to turn over and completely stopped the vehile. Although the car would not start, I was unable to cut the car off completely. It would say ignition on. The lights in vehicle were on. Running the ac caused the car to say high power consumption but there was no way to cut vehicle off without removing the battery to reset the vehicle. Caused the car to malfunction while sitting at a complete stop. Also cause the parking break to engage and I was unable to disengage parking break. A message came across saying parking break unavailable. My safety and others were put at risk because had it happened at any other time a crash would have been caused. It caused a roadway to be blocked off which caused confusion and near accidents.

NHTSA complaint #11606573 — an unverified report by a vehicle owner.

Northville, MI

FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING

The electric park brake makes a loud screaming sound during engaging cycle as I put the gear in park. The sound gets worse during warmer weather. I visited the dealer twice for the same problem and reported it to Toyota. During my visit another highlander came into dealership. It made the same sound when the driver placed it in Park. According to the dealer, this sound is normal. I say it’s not. I have way cheaper cars with Electric park and they don’t make this sound. If the park brake unit fails it’s going to be real costly to repair and may fail while driving and gets engaged.

NHTSA complaint #11604891 — an unverified report by a vehicle owner.

Waterbury, CT

LANE DEPARTURE: ASSIST

The steering technology in this vehicle reads lines on the road that are not correct or valid lanes and almost caused several accidents during the 2 years I had the vehicle. Luckily, I was paying attention and had to jerk the wheel to the correct lane but the steering wheel will force itself to the other false lane. This is extremely dangerous and this is a huge safety issue.

NHTSA complaint #11552496 — an unverified report by a vehicle owner.

Huntingtown, MD

LANE DEPARTURE: ASSIST

The lane assist will not stay turned off, even when it is done manually each time I get in the car. The steering pulls me back when I'm trying to change lanes, making it unsafe.

NHTSA complaint #11552162 — an unverified report by a vehicle owner.

Huntingtown, MD

LANE DEPARTURE: WARNING

The lane assist will not stay turned off, even when it is done manually each time I get in the car. The steering pulls me back when I'm trying to change lanes, making it unsafe.

NHTSA complaint #11552162 — an unverified report by a vehicle owner.

Pineville, LA

FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL

I was driving 50 mph on 28 E in Pineville, Louisiana when I heard what sound like a gunshot. I pulled over and realized my sunroof exploded.

NHTSA complaint #11525473 — an unverified report by a vehicle owner.

Pineville, LA

FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING

I was driving 50 mph on 28 E in Pineville, Louisiana when I heard what sound like a gunshot. I pulled over and realized my sunroof exploded.

NHTSA complaint #11525473 — an unverified report by a vehicle owner.

Pineville, LA

LANE DEPARTURE: BLIND SPOT DETECTION

I was driving 50 mph on 28 E in Pineville, Louisiana when I heard what sound like a gunshot. I pulled over and realized my sunroof exploded.

NHTSA complaint #11525473 — an unverified report by a vehicle owner.

San Jose, CA

FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING

my car experiences intermittent acceleration when applying the breaks. It lunges forward for some reason. It has also not stopped when hitting the breaks hard but lunges as well. I am using the last date that this happened.

NHTSA complaint #11508626 — an unverified report by a vehicle owner.

Providence, RI

FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING

Warning lights appeared while driving on city streets.

NHTSA complaint #11507424 — an unverified report by a vehicle owner.

Clearwater, FL

FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING

Forward Collision Warning and Automatic Emergency Braking isn't functioning as stated in the Toyota Highlander 2021 Owner's Manual. Dealer stated that software tests were conducted and the vehicle's radar and optical sensors are performing in accordance with the test results. However, there is only intermittent warning lights and alarms that are functioning. The dashboard audio and visual alarms only function in rare encounters on approaching a vehicle. The service manager rode with me and when I was approaching a vehicle where an alarm should have sounded or illuminated inside the vehicle, that did not occur. However, the software tests showed that the vehicle was approaching on a collision event that was recorded on the system, but failed to alert the driver. After additional testing, the service manager stated that the vehicle reads stop lights from the vehicle ahead to execute the safety functions of the forward collision warning and automatic emergency braking safety feature. The Owner's Manual doesn't make that claim. In addition, another service manager stated that the system uses artificial intelligence to learn the driver' habits and the system adapts to the driver. The Owner's manual doesn't state that claim either. Lastly, the invoice stated that the owner should read pages 257 and 260 of the Owner's Manual to understand how the system operates. This describes the Dynamic Radar Cruise Control functions and not the Forward Collision Warning or Automatic Braking functions. This information is found on pages 235-238. They missed the problem. My suggestion was that their test only looked at a single variable that may have covered the external sensor operation and didn't test the dashboard internal warning system of the audio/visual alerts inside the vehicle. My recommendation was to seek assistance from the supplier that manufactured this system and seek guidance from their engineering staff. I complained to the Toyota Corporate Customer Servi

NHTSA complaint #11469290 — an unverified report by a vehicle owner.

Clearwater, FL

FORWARD COLLISION AVOIDANCE: WARNINGS

Forward Collision Warning and Automatic Emergency Braking isn't functioning as stated in the Toyota Highlander 2021 Owner's Manual. Dealer stated that software tests were conducted and the vehicle's radar and optical sensors are performing in accordance with the test results. However, there is only intermittent warning lights and alarms that are functioning. The dashboard audio and visual alarms only function in rare encounters on approaching a vehicle. The service manager rode with me and when I was approaching a vehicle where an alarm should have sounded or illuminated inside the vehicle, that did not occur. However, the software tests showed that the vehicle was approaching on a collision event that was recorded on the system, but failed to alert the driver. After additional testing, the service manager stated that the vehicle reads stop lights from the vehicle ahead to execute the safety functions of the forward collision warning and automatic emergency braking safety feature. The Owner's Manual doesn't make that claim. In addition, another service manager stated that the system uses artificial intelligence to learn the driver' habits and the system adapts to the driver. The Owner's manual doesn't state that claim either. Lastly, the invoice stated that the owner should read pages 257 and 260 of the Owner's Manual to understand how the system operates. This describes the Dynamic Radar Cruise Control functions and not the Forward Collision Warning or Automatic Braking functions. This information is found on pages 235-238. They missed the problem. My suggestion was that their test only looked at a single variable that may have covered the external sensor operation and didn't test the dashboard internal warning system of the audio/visual alerts inside the vehicle. My recommendation was to seek assistance from the supplier that manufactured this system and seek guidance from their engineering staff. I complained to the Toyota Corporate Customer Servi

NHTSA complaint #11469290 — an unverified report by a vehicle owner.

Mineral, VA

BACK OVER PREVENTION: REARVIEW SYSTEM BRAKING

The rear cross traffic avoidance does not detect a person on a bicycle or motorcycle. The safety sense 2.5 + was advertised and demoed to detect even a pedestrian walking behind the vehicle. The system on my vehicle does not work as advertised and after taking my vehicle to the Dealer was informed by the service manager that the system is "intermittent at best". This is not what Toyota advertises. Dealerships apparently have no signal strength detection equipment to verify proper operation of this system. I have reviewed multiple videos of this system in operation and there were no indications of intermittent failures. I have contacted Toyota Customer support and am being ignored.

NHTSA complaint #11466817 — an unverified report by a vehicle owner.

Mineral, VA

LANE DEPARTURE: BLIND SPOT DETECTION

The rear cross traffic avoidance does not detect a person on a bicycle or motorcycle. The safety sense 2.5 + was advertised and demoed to detect even a pedestrian walking behind the vehicle. The system on my vehicle does not work as advertised and after taking my vehicle to the Dealer was informed by the service manager that the system is "intermittent at best". This is not what Toyota advertises. Dealerships apparently have no signal strength detection equipment to verify proper operation of this system. I have reviewed multiple videos of this system in operation and there were no indications of intermittent failures. I have contacted Toyota Customer support and am being ignored.

NHTSA complaint #11466817 — an unverified report by a vehicle owner.

Mineral, VA

BACK OVER PREVENTION: WARNINGS

The rear cross traffic avoidance does not detect a person on a bicycle or motorcycle. The safety sense 2.5 + was advertised and demoed to detect even a pedestrian walking behind the vehicle. The system on my vehicle does not work as advertised and after taking my vehicle to the Dealer was informed by the service manager that the system is "intermittent at best". This is not what Toyota advertises. Dealerships apparently have no signal strength detection equipment to verify proper operation of this system. I have reviewed multiple videos of this system in operation and there were no indications of intermittent failures. I have contacted Toyota Customer support and am being ignored.

NHTSA complaint #11466817 — an unverified report by a vehicle owner.

Queens Village, NY Crash

FORWARD COLLISION AVOIDANCE: WARNINGS

The Forward Collision did not activate cause the vehicle to meet into a accident. the car didn't give a Warning, or try to stop itself. took it to the dealer and was told that the system was working properly. but I tested the system in the parking lot, with a cardboard box and the system still didn't activate.

NHTSA complaint #11444627 — an unverified report by a vehicle owner.

Queens Village, NY Crash

FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING

The Forward Collision did not activate cause the vehicle to meet into a accident. the car didn't give a Warning, or try to stop itself. took it to the dealer and was told that the system was working properly. but I tested the system in the parking lot, with a cardboard box and the system still didn't activate.

NHTSA complaint #11444627 — an unverified report by a vehicle owner.

at 5,000 miles Perrysburg, OH

LANE DEPARTURE: LANE KEEP: AUTOMATIC STEERING

The contact owns a 2021 Toyota Highlander. The contact stated while driving 60 MPH, the vehicle inadvertently attempted to navigate the steering and lane direction to the opposite direction of where the contact was attempting to steer the vehicle. This caused the contact to manually steer the vehicle into the center lane. There were no warning lights illuminated. The contact took the vehicle to a local dealer who inspected the vehicle but could not diagnose the cause of failure. The dealer informed the contact that the vehicle lane sensor and steering assist sensor were performing as intended. The contact was concerned that the sensor should be adjusted so that the sensor would not have to adjust so easily while the contact was driving. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 5,000.

NHTSA complaint #11442435 — an unverified report by a vehicle owner.

at 5,000 miles Perrysburg, OH

LANE DEPARTURE: LANE KEEP: STEERING ASSIST

The contact owns a 2021 Toyota Highlander. The contact stated while driving 60 MPH, the vehicle inadvertently attempted to navigate the steering and lane direction to the opposite direction of where the contact was attempting to steer the vehicle. This caused the contact to manually steer the vehicle into the center lane. There were no warning lights illuminated. The contact took the vehicle to a local dealer who inspected the vehicle but could not diagnose the cause of failure. The dealer informed the contact that the vehicle lane sensor and steering assist sensor were performing as intended. The contact was concerned that the sensor should be adjusted so that the sensor would not have to adjust so easily while the contact was driving. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 5,000.

NHTSA complaint #11442435 — an unverified report by a vehicle owner.

Other 2021 Toyota Highlander problems

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