*Median odometer reading when the problem happened, where owners gave one. One complaint can name several problem areas.
Unknown or other
My sunroof exploded while driving on the interstate.
Apr 17, 2026Electrical system
The contact owns a 2023 Mercedes-Benz GLC300. The contact stated that while driving at an undisclosed speed, the speed limit warning system failed to function as intended. The contact stated that while driving 60 MPH, the Heads-up Display (HUD) illuminated a red light and an unknown message about driving too slowly was displayed. The contact stated that the red light illuminated and flashed intermittently. The vehicle was taken to the dealer, and the contact was informed that the failure was common with the vehicle. The vehicle was not repaired. The contact stated that the failure persisted. The contact asked if the speed limit warning system could be deactivated, and the dealer was…
Jan 9, 2023 · 12,000 milesForward collision avoidance › Automatic emergency braking
There are two issues 1) Unsure of the exact date, but about a year or two ago we were driving our car and the car's automatic break system went into effect on a typically busy, 3 lane road despite there not being any cars in front of our vehicle. We took it into the dealership, who confirmed the issue and told us that sometimes the automatic brake mis-identifies the metal plates in the roads to be vehicles. Had there been a car driving behind us at the time this was happening, it could have been a major accident as the speed limit on that road was 45mph. Additionally we had our [XXX] in the car. There were no warning lamps, messages or symptoms of the problem prior to failure. 2) Recently…
Mar 18, 2026Electrical system
I purchased a brand new GLC 300 on May 25, 2023. By June 2, 2023 I was already stranded due to a 12V battery electrical system failure. Since then I have been stranded 8 total times and the vehicle has been in the service department 14+ times for repeated electrical issues (8 of those visits were related to the same 12V battery electrical system failures. The battery was reportedly replaced in 2024-shortly thereafter I began experiencing issues with the collision assist malfunctioning. The alarms would sound seat belt tighten and brakes lock up while driving on the interstate. The theft deterrent alarm wound sound in the middle of the night without provocation. The panoramic roof would…
Jun 2, 2023Engine
Vehicle has a significant engine oil leak without being driven. Engine oil electronic meter still shows engine oil to be in "Ok" range. Vehicle is 2023 with only 19680 miles and is rarely driven till the last 2 months. Other 2023 Model Year MB GLC300's manufactured at the same Bremen Germany plant are already being recalled for engine and fuel leaks, however, this one is not on the list. This vehicle is also the 2.0L Inline 4 engine and may be the same engine as the others being recalled. The others are recalled due to an imperfect seal between the high pressure fuel pump and the tandem oil pump. My vehicle is leaking engine fluid, likely oil at a significant rate without having been driven…
Sep 3, 2025Lane departure › Blind spot detection1 injury
1. Rear Hatch hands free system - closes unexpectedly while loading or unloading car without using feet to trigger system. Hatch will close down and trap driver in the rear, causing bruising on driver and requiring assistance to push hatch back up. Has been into dealer multiple times since this is HUGE risk to animals or small children exiting out of the rear. Dealer finally disabled hands free system. 2. Lane change assist/blind spot warning - Auto believes there's a vehicle in the lane to either side and will stop car from changing lanes, when actually there isn't a vehicle there. Has caused several close calls due to signaling to change lanes the car will then try to pull back into…
Mar 2, 2025Forward collision avoidance
The contact owns a 2023 Mercedes-Benz GLC 300. The contact stated while driving on an access road at 35 MPH, the brake pedal was not depressed; however, the vehicle came to an immediate stop. There were no warning lights illuminated. The contact restarted the vehicle and was able to continue driving normally. The local dealer was contacted and sent a tow truck to pick up the vehicle from the residence for diagnostic testing. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 12,000.
Feb 24, 2025 · 12,000 milesElectrical system
check engine light continues to turn on and off, response from dealer maintenance is this issue is temperature related and just keep driving, not sure how this makes for an effective or safe functioning of a warning light also seems like it can lead to unnecessary trips to and costs at the maintenance garage. This has been a multiple time issue since purchase of vehicle.
Dec 3, 2024
Owner complaints are submitted to NHTSA by the public and are not verified. Shown as filed (NHTSA removes personal details); long reports are shortened.