57 of the
488 complaints filed about the Toyota Grand Highlander
are about the engine —
100% of everything owners reported.
The worst model year for it is 2024.
The contact owns a 2025 Toyota Grand Highlander. The contact stated that while driving approximately 35 MPH, another vehicle struck a rock, and the rock went through the front grille of the vehicle and punctured the inverter radiator, causing a coolant leak and a loss of motive power. The message "Hybrid System Malfunction" was displayed following the loss of motive power. The vehicle was towed to a dealer, where it was diagnosed and determined that the inverter radiator had sustained a puncture and needed to be replaced. The vehicle was repaired. The contact associated the failure with NHTSA Action Number: DP26006 (Engine and Engine Cooling). The failure mileage was approximately 14,300.
NHTSA complaint #11762864 — an unverified report by a vehicle owner.
At 5:16 pm, CST. I was stopped at a stop sign headed west on a 25 mph road crossing a 30 mph road (that does not have a stop sign) in Illinois. After waiting for a an appropriate gap in traffic, I attempted to accelerate though the interesting. I released the brake pedal and attempted to accelerate. The vehicle barely accelerated. The engine seemed to minimally climb in RPM and only accelerated minimally out into the cross road. This lasted approximately 1-2 seconds. AT this point I was fully into the first lane of traffic. I then fully depressed the accelerator to try to get the vehicle to respond and after approximately a 0.5 to 1.0 second delay the engine fully responded and I was able to accelerate out of the oncoming cross traffic. This is by no-means the first time this behavior has happened with this vehicle but it is the first time I'm reporting it to the NHTSA.
NHTSA complaint #11761276 — an unverified report by a vehicle owner.
Dear NHTSA, I am writing to formally report a potential safety defect involving the front grille design of my 2026 Toyota Grand Highlander Limited. Fortunately, my vehicle has not experienced any damage or mechanical failure related to the grille at this time. However, after examining the design of the front grille and the components located directly behind it, I have serious concerns that the relatively large grille openings may allow rocks and other road debris to pass through and strike critical cooling components, including the radiator and other heat exchangers. My concern is particularly related to the potential consequences of such an impact. If road debris were to damage a cooling component, it could result in coolant loss, overheating, warning messages, reduced vehicle performance, or potentially loss of propulsion. If this occurred while traveling at highway speeds, it could create a significant safety risk for the vehicle occupants as well as other motorists. I understand that NHTSA is currently reviewing concerns regarding the front grille design of 2024–2026 Toyota Grand Highlander vehicles. I would like my vehicle and this concern to be included in NHTSA’s review. I believe this issue warrants further evaluation because the concern exists even before an actual failure occurs. A safety defect should ideally be identified and addressed before owners experience a failure that could potentially create a hazardous situation while driving. I respectfully request that NHTSA investigate whether the front grille provides adequate protection for the critical cooling components behind it and determine whether Toyota should provide a protective screen, revised grille design, or another corrective measure. Again, I want to emphasize that I am reporting this as a potential safety defect. My vehicle has not suffered damage or experienced a failure at this time. I am submitting this complaint proactively because I believe the design presents a foreseeable risk
NHTSA complaint #11760478 — an unverified report by a vehicle owner.
The engine would not engage for 4-5 seconds when pulling out of my neighborhood. Gas pedal was all the way down and after a delay, the car rolled forward as if trying to start in 2nd/3rd gear. I am a cautious driver, but this is an unsafe scenario when pulling out into traffic.
NHTSA complaint #11759500 — an unverified report by a vehicle owner.
Sometimes, when trying to accelerate in certain situations, the vehicle accelerator pedal will not respond or the engine stutters and won't immediately respond to input and the vehicle seems to stall. This has been scary several times in traffic. The vehicle originally would throw an engine code on the dash about system failure and was taken into the dealer after several of these incidents and a software updates was performed, but it still happens randomly although now with no code.
NHTSA complaint #11759560 — an unverified report by a vehicle owner.
I continuously have issues accelerating from stop in my max hybrid. the issue is particularly worse when it is warm out. I press the gas and the RPMs drop really low and I barely move through the intersection for a few seconds. Once it finally registers after a number of seconds, the RPMs rev up over 4000. It is very dangerous trying to proceed through an intersection and the car basically stalls when I press the gas. It especially concerns me that I have my child in the car with me and I worry when it is going to act up. I know others have experienced this issue and there was a TSB for 2024 models that had this issue. I have a 2025 and experience this issue. I have had toyota look at it and they said they cant do the TSB since it's bot for my VIN. A solution needs to be found for the the safety of myself and others.
NHTSA complaint #11759592 — an unverified report by a vehicle owner.
During normal highway driving, a small road rock/debris entered through the front grille and damaged the radiator/heat exchanger. The damage caused coolant to leak, and the vehicle subsequently lost propulsion and became disabled. I had to stop driving the vehicle and have it inspected and repaired by a Toyota dealer. The Toyota dealer inspected the vehicle and confirmed that the radiator/heat exchanger was damaged by an outside object and was leaking. The dealer indicated that rocks or road debris can cause this type of damage. The total repair cost was approximately $1,350. I am concerned that the large openings in the front grille allow ordinary road debris to reach the radiator/heat exchanger, which is not adequately protected. A relatively small road object resulted in a critical cooling system failure and sudden loss of vehicle propulsion, creating a significant safety risk, particularly if this occurs while traveling at highway speed. I understand that NHTSA is currently reviewing similar reports involving the grille design and damage to the heat exchanger/radiator on Toyota Grand Highlander vehicles. My vehicle experienced a similar failure. I believe this issue should be investigated as a potential design-related safety defect and that an appropriate protective solution should be considered.
NHTSA complaint #11759004 — an unverified report by a vehicle owner.
road debris entered into front grill though the holes in grill adn damaged condensor fins causing vehicle to loose propulsion. Vehicle would not travel over 25 mph after the incidnet. This is safety issue as vehicle slowed from 55MPH to 25MPH rather abruptly on highway. Multiple lamps came on dash at time of incident and were reatained untill fixed (non warranty repair)
NHTSA complaint #11759168 — an unverified report by a vehicle owner.
While driving on a highway at highway speed of approximately 62 miles per hour, a rock from the highway went through the front grille's hole, and punctured the area of the radiator, resulted in a large loss of coolant, and the vehicle's speed suddenly lost highway speed and lost propulsion on the highway, while driving at a highway speed. Thankfully noone was driving behind me. However, If someone was behind me, they would have hit me from the rear due to my loss of propulsion.
NHTSA complaint #11758880 — an unverified report by a vehicle owner.
I had my car for service to be replace the wheel bearing on the right passenger side. Two weeks after my cooling engine light came out. Took to the dealership and they said there is a leakage in the radiator and needs replacing.
NHTSA complaint #11758752 — an unverified report by a vehicle owner.
Vehicle intermittently fails to accelerate when accelerator pedal is depressed after stopping. Vehicle may move extremely slowly for several seconds and then suddenly regain power. This has occurred while entering/intersecting traffic and has resulted in near-collision situations. Dealer cannot duplicate the problem.
NHTSA complaint #11756305 — an unverified report by a vehicle owner.
I've had consistent issues with the vehicle accelerating and shifting. These include sluggish acceleration, loss of power and sputtering when we've come to a complete stop and starting to move again. We've almost been hit by other vehicles at least over 20 times because the vehicle has failed to accelerate when pulling into a roadway. The car hesitates during acceleration regardless of how much I push the gas. Once it starts to go, it feels as though the car can't shift from 1st to 2nd gear, The RPMs get extremely high while the car is going 25-40 mph and remain there for a few seconds up to ~20 seconds. I am fearful of getting t-boned when my car hesitates while turning at an intersection, going through an intersection or pulling out from a parking lot. I have been stuck in several intersections when traffic was coming toward me, but thankfully those cars had patience and avoided us. I've also found that this issue always happens when the hybrid battery shows that it only has a charge of 3 bars. It seems that the engine, transmission and hybrid battery don't know how to communicate when the battery charge gets that low. This has been happening since Dec 2023 when I bought the vehicle and the dealer has never been able to duplicate or find any error code, they are refusing to fix a known issue when many others are experiencing the same issue. There are Toyota Technical Service Bulletins (TSBs) out there regarding this problem but my dealer told me they won't do anything as it could label my vehicle a lemon. This is creating an unnecessary safety risk for me and my family.
NHTSA complaint #11750786 — an unverified report by a vehicle owner.
After coming to a complete stop at a stop sign or stop light, then trying to go, the vehicle will stall. It will not go when given gas. The first time it happened, I was at a busy intersection with oncoming traffic coming towards me with the pedal to the floor, nothing would happen for 5-10 seconds. It was terrifying. Thank god the car coming towards us went around in time. It then happened again in my neighborhood a week later. Thankfully that time I wasn’t in traffic. I have noted that it seems to happen when very hot outside (Florida July summer) and air is on full blast. Also seems to be happening only during the first trip of the day, within the first 5-10 minutes of said trip. The dealership has not been able to recreate this to see for themselves. I think it would have to be with them overnight and they start it/drive it for the first time that day. It has now happened a total of 3 times since I’ve been driving it (2.5 months). I have 3 children and very worried I will get t-boned one day when it stalls next. I love my car so much so it’s heartbreaking that I have to drive it in fear. No lights/warnings/messages when this happens.
NHTSA complaint #11750573 — an unverified report by a vehicle owner.
This vehicle has just over 18,000 miles on it and is 14 months old. It has a manufacturer design defect that allows small stones or birds to hit and puncture the air conditioning condenser. It is a known defect and Toyota refuses to warranty their product, forcing the consumer to pay out of pocket $1,500-$1,700 for repairs. Oddly, the sister Lexus vehicle has a screen over the condenser to prevent this.
NHTSA complaint #11750610 — an unverified report by a vehicle owner.
Radiator issue summer of 2025, when in back to back traffic at low speeds my vehicle overheated at a stand still took vehicle in to dealership with no real answers. The following summer 2026 same scenario but the engine was smoking. Took into dealership and they stated the connection for the radiator fan was disconnected which meant it was not colling the engine. A month later the AC is blowing hot air when AC is set to the coolest setting, scheduled another appt with dealership likely another radiator issue. Fuel gauge inaccuracy. Manual states 17 gallon tank capacity but my car states empty and can only fill the tank with 14 to 15 gallons. Dealership had no help and stated it does that to protect the hybrid engine. Transmission shifting issues, in the summer hotter temperatures I notice at times the transmission has difficulty shifting in lower gears and really revs up the RPMs to shift sometimes. At times the the transmission shift is jerky or harsh when going speeds form 20- 40 mph.
NHTSA complaint #11750413 — an unverified report by a vehicle owner.
Component: Automatic transmission, 2026 Toyota Grand Highlander Hybrid MAX Platinum AWD. Available for inspection. Purchased new 11/21/2025 at zero miles. Beginning ~2000 miles (est Feb 2026), intermittent transmission malfunction during acceleration: transmission holds gears at elevated RPMs beyond expected shift point, then shifts harshly or shudders violently. Documentation began 6/1/2026; current odometer 8936 miles. Occurs from 22–64 mph, most commonly 30–44 mph, in Normal and Sport modes, after cold starts, extended driving, and brief stops. RPMs typically hang at 3500–4000 before shifting. Documented incidents over the last month: June 1, 2026, 3:20 PM: Approximately 1 min after cold start, turned right at a light to 33 mph. Violent shake and abnormally loud acceleration during gear change. June 2, 2026, 3:00 PM: Turning right and accelerating after driving approximately 1 min, transmission revved high; had to release throttle to force the shift. June 11, 2026, 4:40 PM: After cold start, driving up a small incline about .4 miles away, transmission revved high and delayed shift at 35–45 mph. June 12, 2026, 3:17 PM: After 17 minutes of driving, accelerating from a cloverleaf around 25 mph to 64 mph, revved at 4000 June 19, 2026, 3:00 PM: After 2 hours of driving and a 5 min stop, turning right out of a shopping center, transmission hung up three consecutive times at 35–40 mph, RPMs at 3500–4000. June 20, 2026, 11:17 AM: Accelerating off a cloverleaf at 57 mph. RPMs hung at 4000 before shifting. June 30, 2026, 10:23 AM: Pulling out of neighborhood after backing out of driveway. RPM hang at approximately 22 mph, then again at 43 mph Safety risk: Unexpected RPM surge and violent gear change during acceleration on highway on-ramps, cloverleaf merges, and intersections creates unpredictable vehicle response at speed, presenting collision risk to driver and surrounding vehicles Dealer/service: Not confirmed by dealer. Assessed at ~6000 miles with no issues found
NHTSA complaint #11747505 — an unverified report by a vehicle owner.
While driving my 2024 Toyota Grand Highlander Hybrid AWD at highway speed with only 16,755 miles on the vehicle, multiple warning messages suddenly appeared, including warnings related to the engine, hybrid system, AWD system, and other vehicle functions. The vehicle instructed me to pull over immediately and significantly reduced power output, making it difficult to maintain highway speed and safely maneuver through traffic. I was able to reach the shoulder and had the vehicle towed to a Toyota dealership. The dealer diagnosed a punctured radiator caused by a rock or similar road debris that allegedly passed through the front grille and struck the radiator. The dealer confirmed that coolant loss from the puncture triggered the vehicle's protective reduced-power mode. This failure created a significant safety risk. A sudden loss of power while traveling at highway speed increases the risk of rear-end collisions and other accidents, particularly in heavy traffic where drivers may not expect a vehicle to rapidly decelerate. There were no warning lights, messages, leaks, drivability concerns, or other symptoms before the incident. All warnings appeared suddenly at the time of failure. Toyota has declined warranty coverage, classifying the damage as a road hazard. However, I believe this may indicate a design defect. I have identified numerous reports from other GH owners describing nearly identical failures involving rocks penetrating the radiator through the front grille, often at relatively low mileage. These reports suggest the radiator may be inadequately protected from ordinary roadway debris. My concern is not simply radiator damage, but that a small piece of road debris encountered during normal driving can disable a critical component and cause the vehicle to enter a severe reduced-power mode at highway speed. I request that NHTSA investigate whether the front grille and radiator protection design of the Grand Highlander creates an unreasonable safety risk
NHTSA complaint #11746510 — an unverified report by a vehicle owner.