There are 3 owner-reported brakes complaints for the 2023 Mercedes-Benz GLS-Classin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
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.
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.
when coming to a stop and applying the break, the transmission stalled. a warning was issued around lane keeping assist and a second warning. Then the transmission light was on. It was not at risk in the moment because no one was behind me and I was coming to a stop sign. If it prevented me from stopping I might have gone through the stop sign It is at the dealership today to service. no warning lamps, messages or other symptoms.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 26, 2026