In most circumstances the adaptive cruise control (ADC) works well. There is one case where it does not, however. When ADC is active and the vehicle immediately in front shows, perhaps to make a turn, the ADC-equipped vehicle slows appropriately. The problem: Once the front vehicle is *well clear* of the driving lane, often operating 90 degrees to the marked lane on a perpendicular roadway, the ADC-equipped vehicle delays in sensing this and dos not resume the set speed. The effect is for traffic behind the ADC-equipped vehicle to become exceedingly annoyed and a chain-reaction of braking results. Drivers operating behind the Mercedes-Benz have a reasonable expectation that when the traffic in front of the ADC-equipped vehicle is clear the latter will accelerate. This expectation is not met in practice -- ever. The result is near-miss rear end collisions This exact same issues was also observed on a 2025 Mercedes GLE450.

Source: NHTSA complaint ODI #11748273 · view all complaints for this vehicle at nhtsa.gov

The contact leased a 2026 Mercedes-Benz GLE450 4Matic. The contact stated that while driving at an undisclosed speed, there was an unknown warning light flashing on the instrument panel. The speed limit was displayed and was flashing. The contact turned off the feature, but the light continued to flash on the instrument panel. The vehicle was taken to the local dealer on two occasions, where an unknown diagnostic result was provided. The manufacturer was working on an update for the fix. The vehicle was not repaired. The manufacturer was mailed a letter, and a subject matter expert contacted and informed the contact that there would be a fix within the first quarter of the year. The failure mileage was unknown.

Source: NHTSA complaint ODI #11728321 · view all complaints for this vehicle at nhtsa.gov

I was driving in I75 highway south in Michigan and heading to Ohio. I had around 70 mil/hr ish speed and was trying to pass a commercial truck. I Just turned on rear window wiper to clean it and once it started to work, the vehicle had a very hard brake for a couple seconds which the my seat belt pushed me hard to the seat to avoid of my head to go forward to windshield. Fortunately it was very quick brake and didn’t caused any accident, but I was worried that it was repeated again and had a lot stress until I arrived at the destination. I am guessing probably either park brake was engaged without touching it(software or part issue) or the sensors for front and emergency collisions had the bad function.

Source: NHTSA complaint ODI #11705424 · view all complaints for this vehicle at nhtsa.gov

If the driver seat belt is pulled too quickly from the retractor mechanism, the seat belt can not be retracted and then pulled across the drivers lap UNLESS the car is stopped and the driver door is opened. Example. I pull up to a toll booth. I release the seat belt from my lap to access my wallet. I pay the toll and start to drive away as I then try to reattach the seat belt. I cannot get it to pull across my lap UNLESS I stop the car and open the door. This resets the belt mechanism. This is unacceptable and a safety issue. Mercedes has been notified of this design flaw and refuses to address the issue. The driver should be able to reattach the seat belt without stopping and opening the car door. Driver safety is of paramount importance.

Source: NHTSA complaint ODI #11753052 · view all complaints for this vehicle at nhtsa.gov