2026 Toyota Grand Highlander Engine Problems

I was traveling while on cruise with the max distance set between another vehicle and I. A rock popped up and managed to propel itself through the poorly designed and inadequately designed grill and into my condenser. I am apart of many Highlander support groups and this seems to be an issue with a lot of people. They have to take it upon themselves to install a mesh to prevent road debris entering through their grill. This could have been a significant safety issue had it been my radiator. Now I am out $2,000 due to faulty design on Highlander grill and I haven’t even made my first car payment yet.

NHTSA ID

11776862

Incident

Nov 5, 2026

A small pebble or rock was thrown from another moving vehicle and it was able to get through the large holes of the grill and punctured the radiator. There isn’t adequate protection for the radiators from such common road debris.

NHTSA ID

11774554

Incident

Oct 25, 2026

My Toyota Grand Highlander Hybrid Limited has 16000 miles. Yesterday, 5 vehicle alerts appeared simultaneously: Check Engine, AWD system, Drive-Start control system, Intelligent clearance Sonar, and Hybrid system. The vehicle has reduced power and check engine light is illuminated. I towed the vehicle to dealership. They found damage to inverter radiator causing a leak of coolant. Dealership mentioned that this could be because of flying debris hitting the vent. I am requesting a goodwill technical review and repair of the same. Referencing to the NHTSA defect petition DP26006 where people have encountered similar issues with the grand highlanders from 2024-2026.

NHTSA ID

11770851

Incident

Oct 12, 2026

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 ID

11760478

Incident

Aug 28, 2026

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 ID

11759168

Incident

Jul 1, 2026

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 ID

11759004

Incident

Aug 19, 2026

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 ID

11747505

Incident

Jun 1, 2026

Failed System: Fuel Injector Failure (?) at high speeds, under load (uphill), causing an immediate and life threatening loss of power. While traveling on the highway, going up mountainous areas, the vehicle loses power and shakes violently. During multiple repairs/visits, the dealerships state that it is the failure of fuel injectors. They are replaced, and it happens again with the same explanation. Safety: Three times my family has lost power at 70mph while traveling uphill surrounded by many cars. The last event ended in a a scary and close interaction with an 18 wheel truck that was unable to stop as we lost power. Dealer Confirmation: The dealer has confirmed, on two separate occasions, that the fuel injectors needed replaced. The vehicle has 3,000 miles on it. At 2,000 miles, damage was found to the fuel injectors. They were replaced and the car was placed back in my possession. At 3,000 miles, the incident occurred for the 3rd time and damage was again found with the fuel injectors. Inspection: Dealerships as well as Toyota's field technician have inspected/repaired the vehicle 2 times and is currently at a dealership for the 3rd time. Warning messages: After the incident occurs, multiple warning lights appear (check engine and hybrid system malfunction).

NHTSA ID

11740216

Incident

Apr 17, 2026

I purchased this vehicle new from Toyota of madison in Indiana on 3/26/2026. It had 300+ miles on it. Had it for just a week before this warning light came on while idling or driving very slowly..… High Coolant Temp. Pull over in a safe area immediately. My temperature gauge was in the red. I pulled over. Called closest dealership who stated closed for Easter. After several hours of personal researching on the internet of a potential cause , I examined the engine only to find that my Radiator Fan had been UNPLUGGED!! No wonder the engine was overheating. I currently own 4 corollas, one 2025 tundra, and one sienna. I have never had this issue with Toyota. Why was the radiator fan unplugging and Who unplugged this radiator fan and forgot to plug it back?????

NHTSA ID

11729249

Incident

Apr 4, 2026