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What 10 owners told NHTSA about the 2023 Mercedes-benz GLS

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (10)Brakes (4)Engine (4)Driver assistance (2)Electrical system (2)Fuel system (2)Body & structure (1)Lane Departure (1)Transmission & drivetrain (1)Wheels (1)

2 of 10 complaints match · Driver assistance · clear filters

Apr 14, 2025BrakesDriver assistance

The car recently underwent a software update at the dealership for a backup camera issue. When I was driving home on the highway, the car suddenly braked and the seat belts automatically tightened up. This happened 3 additional times on the highway about 5 days later. I had turned off the automatic braking system and it seemed to go away. Then, with the system off, we experienced this again yesterday while on the highway at 70mph. The braking lasts for 1-3 seconds. There is no audible alert or dashboard display. IT renders the car quite unstable as it feels as though the rear brakes are being activated before the front. I reported this to the dealership and they want to inspect the car.

NHTSA ODI 11654449

Oct 2, 2024BrakesDriver assistance

There have been 3 incidents where the car responded to unknown stimuli by braking hard. 3 months ago it happened while making a left turn through an intersection, driving about 10 mph the brakes unexpectedly locked up, luckily the person behind me took evasive action and didn't hit me; 2 weeks later it happened again, I was driving on I-45 attempting to pass slower drivers, the brakes dramatically engaged while I was driving over a slight hill, today it happened again when it mistook a vehicle in a different lane of traffic, and performed a hard brake evasive measure even though there was no chance of collision and nothing in front of the vehicle.

NHTSA ODI 11617794

Working with the data? Download all 10 complaints as CSV · fetched from NHTSA July 20, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2023 Mercedes-benz GLS verdict →