2024 Toyota Grand Highlander: sudden loss of power

Filed Oct 24, 2026 · Transmission · MD

Transmission Whining Noise Detected, Automatic Shifting Difficulties, Reduced Power & Acceleration Concerns. Dealer inspected and confirmed transmission failure. Required Dealer replacement under power train warranty. Defect known to exist in Toyota 6 speed Automatic U80A transmissions. Transmission is known to be defective and unreliable, potentially causing catostrophic injury to persons and property with use and operation.

Filed Sep 4, 2026 · Transmission · TX

When ambient temperature are over ~90 the vehicle will lose power during acceleration. This happens typically in the speed range of ~20-35mph. The vehicle’s rpm will spike high but lose the ability to increase speed or shift gears. This occurs ~ 40-50% of the time when over 90 degrees. On several occasions we were forced to abandon merging onto the highway because the vehicle wasn’t safely able to accelerate to match the speed of vehicles on the highway. We reported this issue to our local Toyota dealer September 2025. After reviewing the vehicle they said nothing was wrong. We had them drive it longer and they agreed the vehicle had these issues. The dealership spoke with Toyota and they confirmed there was an issue for our vehicle and a lot of others and they had no fix for it. That was September 30, 2025; Toyota Brand Engagement Center Reference # 250923001413. There has been no communication from Toyota or our dealer since then. The safety issue with the vehicle is a major concern in operation of the vehicle and with the hot climate we live in, is putting our occupants and others on the road at risk and we feel Toyota needs to be held accountable for finding the issue(s) and correcting them.

Filed Aug 23, 2026 · Fuel system · NY

During driving on a highway at highway speed (not off-roading), A road debris or rock went through the front grille's hole and damaged the cooling system which leaked coolant and i experienced a loss of power and propulsion while driving on highway, as a result of this issue.

Filed Jul 16, 2026 · Engine, Fuel system · IL

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.

Filed Jun 25, 2026 · Electrical, Engine · MO

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 the federal safety agency investigate whether the front grille and radiator protection design of the Grand Highlander creates an unreasonable safety risk

Filed Aug 20, 2025 · Acceleration, Engine · IL

I've had consistent issues with the vehicle accelerating and shifting. These include sluggish acceleration, loss of power, sputtering, and limp mode. We've almost been hit by other vehicles almost 10 times because the vehicle has failed to accelerate when pulling into a roadway. The vehicle will start to accelerate slowly, then stop, then 5-10 seconds later will surge forward will the engine revs very high and is delayed shifting into 2nd gear. I've told my Toyota dealership about this numerous times but they keep telling me that there's no issue but there clearly is being that many others are experiencing the same exact problems. There's never been a warning lamp or message when this happens. This is a huge safety issue and my family is extremely lucky that we haven't been involved in a serious accident.

Filed Jul 1, 2025 · Electrical, Engine · MD

Over 1.5 years of owning my new 2024 grand Highlander platinum hybrid pro max I have had multiple incidents (6 documented now with toyota) where after coming to a complete stop I go to accelerate and the car shutters,sputters,lunges, and even looses power or goes into “limp mode”. I have been almost hit several times now by oncoming traffic because my grand Highlander completely loses power. It will not accelerate. After 5 seconds I typically hear loud groaning noises followed by two loud bangs and two violent lurches forward before my car finally regains power. No warning lights popped up on my dash any of the times my car has lost power. My dealership keeps telling me “no problem found” and that I am the only one with this issue. This is false. There are many complaints online and finally after I did not give up the dealership pulled a comprehensive RoB scan/report on my car and found multiple transmission failure codes on the transmission system/TCM. One “lack of acceleration code” was even dated two weeks before I bought my brand new grand Highlander with toyota. I received my grand Highlander with 6 miles on it. I was the first owner. My PDI “pre-delivery inspection date was one week after this transmission failure code”. When I presented this to toyota reps who finally met with me at the dealership they had nothing to say. Toyota knows about this problem and they do not know how to fix it. It is a serious safety issue and I refuse to allow someone to get hurt because Toyota will not be honest and relay this known issue. After the dealership and toyota reps told me I was the only one with this issue toyota officially released a service bulletin in March 2025 for a TCM flash reset/update to address sluggish acceleration, loss of power, and limp mode with the transmissions TCM when the hybrid systems battery is at 33% or less. My dealership installed the TCM update about 1.5 months ago and unfortunately my car has had two more instances since with loss of power.

Filed Oct 16, 2024 · Transmission · CA

Specifically the model: 2024 Grand Highlander Hybrid Max. immediately new off the dealer lot when driving between 0-40mph, there is a transmission issue. In real life situation of stop and go, and needing to accelerate after making a right turn out of a driveway or stop sign on to flowing traffic, often times it feels as if the gear is shifting too high or skipping causing the car to lose power/ rpm and the vehicle chugs, before skipping back to the correct gearing and accelarating. I'm not sure how to describe it but I feel it is a safety risk especially if there are cars coming behind you. I have taken this into Hamer Toyota 2 times, but they can't seem to recreate the issue. However, my wife goes through this almost every day during her commute to and from work. Imagine driving a manual transmission and accelerating on 1st or 2nd gear, and all of a sudden the gear shifts to 4th or 5th gear, causing loss of power or rpm and due to natural instinct of depressing the accelerator further for power and the gear now shifting back and clutching grabbing at 1st or 2nd gear with the accelerator depressed further down than the beginning. This causes a jerking motion of our body in the car, because the car loses power, the all of sudden jerks back into power. I have attached URLs to people complaining about this besides myself. I'm seeing that toyota released a TBS to update software, but it seems its not readily available every time I call, or they need to recreate this before anything is done. I think this is a big safety concern and eventually cause accidents by getting rear ended. I'm sure other drivers think we can't drive because of not being able to speed up then rocketing forward. help! [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 6, 2024 · Electrical, Engine · CA

I have had 2 intermittent issues since I bought this vehicle brand new. 1) Hard, Jerky shifting from 1-2 or 2-3 gear 2) Huge safety issue regarding loss of power and inability to accelerate from a stop even though the car is on and in drive. This has happened to me multiple times and is very intermittent so it is hard to replicate. This has happened when I am attempted to accelerate from a complete stop and the car begins to move but then does not accelerate at all. Almost as if the powertrain shut off even though it was moving under its own power a fraction of a second ago. This has happened to me multiple times with my entire family in the car as we attempted to enter intersections leaving the car powerless with oncoming traffic. Thankfully we were not hit by another car but could have been.

Filed Aug 26, 2024 · Electrical · 7,000 miles · CA

The contact owns a 2024 Toyota Grand Highlander. The contact stated that while the vehicle was parked, it was discovered that the key fob lost power causing the key fob to become undetected inside the vehicle. The contact was not able to lock or start the vehicle due to the failure. In addition, there was a beeping sound coming from the vehicle. The dealer was not contacted. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 7,000.

Filed Jul 20, 2024 · WI

After coming to a stop the vehicle will not accelerate as it should. A severe loss of power as it will only advance very slowly for 10 to 15 seconds. This is always in an intersection, so it is dangerous. Seems to happen mostlyin hot weather when the A/C is on.