2024 Toyota Grand Highlander Transmission Problems

Your brake pedal went completely to the floor with no resistance, and your brakes failed to stop the vehicle even when you pumped them repeatedly. You also heard the engine revving unexpectedly. This loss of braking forced you to steer into a yard to avoid traffic, resulting in a crash with a retaining wall, tree, and street sign that caused the vehicle to roll. All airbags deployed and you required hospitalization. The vehicle was totaled. The issue appears to involve a combination of brake system failure and unexpected engine acceleration that occurred simultaneously.

Your transmission has been identified as defective and needs to be replaced, according to your dealership. Toyota has faced multiple lawsuits regarding defective UA80 transmissions since 2016-2017, and your 2024 Grand Highlander is listed as an affected vehicle. The transmission could fail at any time, which poses a safety risk. Replacing the transmission will involve removing and installing a new or rebuilt transmission unit.

When accelerating from a complete stop, your vehicle intermittently hesitates and fails to respond to the gas pedal for a variable amount of time before suddenly lurching forward—similar to a slipping bicycle chain. This lag has been happening repeatedly over more than a year and has gotten worse, creating a safety risk when pulling into traffic. Your dealership has been unable to reproduce the problem and a software update didn't help. The issue may require a transmission control module reprogramming, transmission fluid service, or internal transmission inspection to diagnose the root cause.

Your Grand Highlander is experiencing unpredictable acceleration and shifting problems, including sluggish starts followed by sudden surges and delayed shifts into second gear. This creates a serious safety risk when merging onto roadways, as the vehicle fails to accelerate on demand, and you've narrowly avoided multiple collisions. No warning lights appear before these episodes occur. The issue likely involves fuel delivery, engine sensors, or transmission control and may require diagnostic scanning and potential component replacement or reprogramming.

Your Grand Highlander is experiencing two problems: hard, jerky shifting between gears, and intermittent loss of power during acceleration from a stop—even though the engine is running and the car is in Drive. When this happens, your car may start moving but then stop accelerating entirely, as if the engine suddenly lost power, which has created dangerous situations when entering intersections with traffic. The problem is difficult to diagnose because it occurs randomly and is hard to reproduce. Your dealer will likely need to perform a comprehensive diagnostic scan of the transmission and engine control systems to identify the cause.

Your car sometimes stalls or won't accelerate when you press the gas pedal from a complete stop, even though you're applying enough pressure. This happens unpredictably and has put you in dangerous situations with oncoming traffic. The issue may involve cleaning or replacing fuel injectors, checking the fuel pump, or diagnosing engine control module problems.

**Vehicle:** Toyota Grand Highlander Hybrid Max **Issue:** On high-temperature days, when the A/C is running at full capacity, the vehicle occasionally fails to accelerate from a stop. This issue persists even after applying the recommended ECM update.

Your Grand Highlander randomly loses power when accelerating from a complete stop, forcing you to push the gas pedal hard just to barely move forward. This has created dangerous situations, such as when you couldn't complete a left turn in an intersection. Toyota has issued a technical service bulletin and performed an engine computer (ECM) update, but the problem continues to occur. The issue may require further diagnostic work or additional reprogramming of the engine control module.

while the engine has not warmed up, when its hot and air conditioning is on high, vehicle does not respond to the gas pedal while trying to accelerate from a stop. vehicle hesitates on acceleration. I feel this is a safety problem, because I need the car to merge quickly onto the road from a stop.

Your vehicle has experienced multiple instances where it failed to accelerate when you pressed the gas pedal, leaving you stranded at idle speed in traffic. In these events, the accelerator pedal had no response, forcing you to coast to the shoulder; after a minute or two, the engine gradually became responsive again but remained sluggish until you reached about 20 mph. No dashboard warnings appeared, and there were no obstructions that should have caused this behavior.

Your car loses power during acceleration right after startup, causing it to shutter and not move when you press the gas pedal at stop signs or traffic lights. This has happened three times and nearly caused accidents, even though the dealer replaced the entire hybrid powertrain and the issue continues to occur randomly without any warning lights. The problem hasn't been replicated at the dealership, but you've reported it multiple times. A technician will likely need to diagnose the hybrid system's power delivery and fuel injection timing.

Your CV axles may be faulty and making clicking or clunking noises when you turn, which started early in your vehicle's ownership and has gotten progressively louder. While Toyota has fixed this issue in newer production models, your vehicle hasn't been recalled yet, even though multiple dealerships have had to replace these axles. If a CV axle fails completely, you could lose control of your vehicle, which is a serious safety concern. The fix will involve having a Toyota dealership inspect and replace the faulty CV axles.

Your car hesitates when you accelerate from a stop, especially at intersections, and seems reluctant to shift out of first gear—the engine revs stay around 4500 RPM while you're only going 25-40 mph. This unpredictable problem has happened randomly since you bought the car and creates a safety concern when crossing intersections or merging into traffic. Your dealer found a transmission acceleration error code and applied a software update, but the issue persists. The fix will likely require further transmission software updates, reprogramming, or potentially transmission service.

Your car experiences noticeable lag when accelerating and shifts harshly when going into reverse, problems that started shortly after purchase. You've taken it to the dealership multiple times, but no warning lights appear on your dashboard. The dealership refused to confirm in writing whether the vehicle is safe to drive, and they denied your requests for a loaner vehicle while investigating the issue and during the repurchase claim process. The fix will likely involve the dealership diagnosing and servicing the transmission and engine control systems.

Your instrument panel has failed, and Toyota issued a recall (Campaign 25V595000) to fix it, but the dealer says the required parts aren't available yet. You're also experiencing shuddering when driving above 70 MPH, which was diagnosed as an axle leak—a problem that wasn't caught earlier because your failed instrument panel couldn't display warning lights. The axle was repaired but the shuddering continues, and Toyota hasn't provided assistance despite the recall delay.

Your front axle assemblies were replaced under a Toyota service bulletin at 20,000–25,000 miles due to a clicking noise, but the dealer installed outdated parts that were supposed to be superseded by newer updated versions. Your axles are now failing again at 50,000 miles with the same clicking noise, but the dealer and Toyota won't fix them because they can't reproduce the problem in their shop. Toyota has acknowledged the issue was caused by insufficient grease in the CV joint boots and released updated part numbers, but your car still has the old defective parts installed. Getting this repaired will likely require the dealer to install the newer, updated axle assemblies (part numbers 43420-0E341 and 43410-0E521) instead of the obsolete originals.

Your 2024 Grand Highlander had both front axles replaced around 20,000-25,000 miles due to a clicking noise and vibration when turning. At 50,000 miles, the same clicking noise has returned, especially in cold weather until the car warms up. The dealer has visited three times but cannot reproduce the problem and won't replace the axles again. The issue may require replacement of the CV axles, and possibly a more comprehensive repair or redesign to prevent recurring failures.

Your Grand Highlander made abnormal banging and clanking sounds when you tried to reverse, and the vehicle briefly wouldn't move backward even though it worked normally after restarting. You also heard loud clanking while driving, and a wrench warning symbol appeared on your dashboard along with other warning lights. The dealer couldn't reproduce the problem during testing, so no repair was made, but you plan to bring it back for further diagnostics.

Your car makes a clicking sound when you turn the steering wheel left or right while accelerating, and this has been happening for about 5 months. The dealership couldn't reproduce the sound during inspection but mentioned the Grand Highlander has a known front axle issue. You believe this is a safety concern that hasn't been fully resolved despite Toyota's prior awareness.

While slowing down on a highway off-ramp (twice in similar situations), your car suddenly jerked back and forth as if the brakes were being rapidly slammed on and released repeatedly for about 2 seconds, even though you weren't pressing the brake pedal that hard. The sensation felt similar to the car's emergency braking system activating, as if it detected an obstacle ahead. The car returned to normal driving immediately after, with no warning lights appearing. This issue may involve the brake system or forward collision avoidance system engaging unexpectedly on downhill slopes.

Your CV axle has needed replacement twice already at just 18,000 miles. Toyota issued a technical service bulletin indicating they redesigned the CV axle mid-production, and vehicles built before that change may continue to experience premature CV axle failures. You may want to discuss with your dealer whether your vehicle was built before the redesign and what long-term options are available.

Your vehicle suddenly lost power while driving, but regained it when you released and reapplied the accelerator pedal. The car then displayed a warning message indicating both the accelerator and brake pedals were being pressed at the same time, even though they weren't. Additionally, you experienced false seat belt warnings when no passengers were present, and the radio stopped working until you restarted the vehicle—these issues became recurring problems. The malfunctions suggest a possible electrical or sensor issue that causes intermittent false readings and system failures that temporarily resolve with a restart.

Your 2024 Grand Highlander Hybrid Max experiences transmission problems during low-speed driving (0-40 mph), especially when accelerating after stops or turns. The transmission appears to shift to an inappropriately high gear, causing a loss of power and engine roughness before suddenly dropping back to the correct gear with a jerking sensation. This creates a safety concern when merging into traffic or accelerating from stop signs. Toyota has released a software update to address this issue, which would be installed at a dealership.

Several times per week, when I go to accelerate after being at a complete stop, my vehicle hesitates and does not pick up power. It very slowly accelerates and feels as if it’s going to stall, then suddenly revs up and accelerates, but revs up higher than it should before finally getting to the appropriate speed/RPM.

On hot days when your air conditioning is running at full capacity, your vehicle may occasionally fail to accelerate from a stop, even after the recommended engine computer update was applied. This lack of reliable acceleration is especially dangerous when you need to turn across oncoming traffic or enter a busy street, as your car could be left stalled in the path of other vehicles. The fix will likely involve diagnosing and updating engine control systems or checking fuel and ignition components to restore proper acceleration.

Your vehicle may not respond quickly when you press the accelerator from a complete or rolling stop, especially when the air conditioning is on high or during extremely hot weather. This problem started after a recent software update and creates a safety risk when merging onto busy roads, as delayed acceleration could cause a crash. The issue may be related to the TSB-0017-24 software update performed to fix a separate shifting hesitation problem.

Your engine loses power when starting from a stop or driving at low speeds, causing it to stumble and almost stall. When you press the accelerator, the vehicle doesn't respond for several seconds before suddenly moving again, which has created dangerous situations. No warning lights appear, and your dealer found no diagnostic codes despite two service visits. The issue likely involves fuel delivery, ignition timing, or engine sensors that need diagnosis with advanced testing equipment.

Your Grand Highlander started making a clunking noise when turning left within the first month of ownership, which got progressively louder and appeared when turning right as well. The dealership initially blamed a heat shield, but the noise persisted, and you later experienced a dead battery that required replacement. A Toyota field technician diagnosed a bad left CV axle, which the dealership said was safe to drive despite the risk that a complete failure could cause the vehicle to stop suddenly or lock up the tires, potentially leading to an accident and additional transmission damage. Fixing this will likely require replacing the damaged CV axle.

Your 2024 Toyota Grand Highlander Hybrid is making an intermittent knocking or clicking noise that seems to come from the drivetrain, especially during low-speed turning and light acceleration—particularly on the first drive after sitting overnight. The noise is unpredictable and hasn't been reproduced at the dealership yet, but multiple drivers have heard it. Your dealer may need to inspect the axles, CV joints, and drivetrain components to identify the source and rule out any developing mechanical issues.

When you start moving from a complete stop, your car sometimes hesitates and doesn't accelerate smoothly to full speed. This could happen intermittently rather than every time you drive.

Your vehicle occasionally feels sluggish or slow to accelerate when starting from a stop, but the problem is inconsistent and difficult to reproduce. This could indicate an issue with fuel delivery, engine performance, or transmission response. A technician may need to diagnose the fuel injectors, fuel pump, or engine control system to identify the cause.