2024 Mercedes-Benz GLC 300 Problems

While driving the vehicle the engine started running rough, check engine light illuminated and it would not accelerate above 40 mph. There are 29,100 miles on the vehicle, it's been serviced on schedule by Mercedes and is owned by me since new. It is especially concerning due to the acceleration topic which could have been catastrophic if I were trying to merge into traffic. Dealer service say the camshaft bearing needs to be replaced. It seems this is very premature for the mileage on the vehicle.

•Incident Details: •Both sudden shutdown incidents •“12V Battery” warning (first incident) •“Stop - Switch Off Vehicle” warning (second incident) •That it happened with children in the car on a tollway Safety Concerns: •Loss of power steering/braking •Risk of collision •Repeated failures on a 1-year-old vehicle

When stopped at a light or stop sign, Vehicle will Jerk forward as If hit from behind. Very surprising and dangerous. Very intermittent. The has happened many times. Vehicle will at times have rough downshifts. Ie. overdrive (9th) to (8th) gear. also intermittent. This has happened multiple times. Vehicle was taken to the dealer twice for a total of 50 hours in the shop. The first service time no problem was found, diagnostics did not show problem. Aug 22 to Aug 30, 2024. The second service time Oct 3 to Nov 14, 2024. Problem was duplicated by the technician. Vehicle diagnostics still did not show a problem. Technician replaced the transmission valve body, did various software checks at the request of the factory. The engine control unit was then changed based on data supplied to the factory. At this point technician checked the car and dealers believes car is fixed. Vehicle has been returned to us on Nov 14 2024. We have requested the vehicle be bought back or replaced.

The contact owns a 2024 Mercedes-Benz GLC300. The contact stated that while driving at an undisclosed speed, the audible alarm activated and several warning lights illuminated. The contact stated that all the warning lights went off except the check engine and the low-battery warning lights. The vehicle was taken to the dealer. The vehicle had not been diagnosed or repaired. The contact stated that the vehicle was previously taken to the dealer on three occasions because of electrical or software failure. The manufacturer was made aware of the failure and a case was filed. The failure mileage was approximately 2,174.

While driving my 2024 Mercedes-Benz GLC 300 on California highways, the vehicle has repeatedly experienced sudden uncontrolled deceleration, unexpected transmission downshifts into 2nd gear, severe transmission jerking, and complete loss of accelerator response. The first major incident occurred on March 7, 2025, while traveling on Interstate 5 at approximately 70 mph. The transmission suddenly jolted and downshifted directly into 2nd gear. The vehicle immediately lost power and slowed to approximately 20 mph without warning. I exited the highway and restarted the vehicle before it temporarily resumed normal operation. A second major incident occurred on May 7, 2026, while driving on Interstate 5 near Flag City, California at approximately 65 mph. The vehicle suddenly decelerated uncontrollably to approximately 20 mph. The transmission again shifted directly into 2nd gear, and the accelerator pedal became completely unresponsive. I was forced to make an emergency stop on the shoulder of the freeway with hazard lights activated due to the risk of being rear-ended by high-speed traffic and trucks. A third incident occurred on May 13, 2026, while accelerating onto Highway 99 in Modesto, California. During a shift from 4th to 5th gear, the transmission jerked violently and the vehicle suddenly lost power while merging into highway traffic. The vehicle has been taken to Mercedes-Benz of Stockton multiple times for diagnosis and repair attempts. The dealership has performed software updates and extensive testing, and dealership personnel have personally verified the transmission defect during road testing. Mercedes-Benz engineering has also become involved in the diagnosis process. However, the defect remains unresolved. This defect creates a serious highway safety hazard due to sudden loss of propulsion, uncontrolled deceleration, and loss of accelerator response while driving at freeway speeds.

•Incident Details: •Both sudden shutdown incidents •“12V Battery” warning (first incident) •“Stop - Switch Off Vehicle” warning (second incident) •That it happened with children in the car on a tollway Safety Concerns: •Loss of power steering/braking •Risk of collision •Repeated failures on a 1-year-old vehicle

3/31/26 2pm After highway driving - 3 miles/35 mph tried to brake- Immediately something was wrong with the brake as and it felt spongy/mushy/unresponsive. Car did not slow until I pressed the brake fully to the floor. The car did stop &was alarmingly unresponsive. Around this time,noticed the white BRAKE light illuminated. Continued to drive - terrified. Had to brake VERY HARD to get car to slow/stop. at home, Quick google search had me try turning on and off parking brake - tied this 5-6 times and white BRAKE light went off and I could brake/stop car. Bought car to Mercedes for service for 4:20 appointment - expressing incredibly strong reservations to Will Bane -and fear about driving car. He assured me as it is braking it should be fine. 04/01/2026 -notified car was ready for pick up/text stated: "Service is complete, everything looked good on the inspection report. No codes in the system for the brake concern and the brakes are currently working as designed" at pickup - and prior in text to will bane - i expressed significant concern about future braking issues. was told it was a "software issue and they updated it" and given a card for roadside assistance There was a recall campaign (2026010002/25p5496612) and codes were cleared as part of this unrelated recall. Brake fluid exchange was performed PRIOR to brake diagnosis Bottom line - I have significant concerns about braking.

The contact owns a 2024 Mercedes Benz GLC 300. The contact stated that while attempting to park, the vehicle experienced unintended acceleration causing the contact to lose control of the vehicle and crash into a wall, another vehicle, and two poles where it came to stop when crashing into the second pole. During the unintended acceleration, the contact depressed the brake pedal to control the vehicle however it failed to respond. No air bags deployed. The contact sustained chest, neck, and back injuries and an ambulance transported her to a hospital. A police report was filed. The vehicle was towed to an independent mechanic by the insurance company. The vehicle was not repaired. The dealer was not contacted. The manufacturer was not made aware of the failure. The failure mileage was approximately 97,000.

•Incident Details: •Both sudden shutdown incidents •“12V Battery” warning (first incident) •“Stop - Switch Off Vehicle” warning (second incident) •That it happened with children in the car on a tollway Safety Concerns: •Loss of power steering/braking •Risk of collision •Repeated failures on a 1-year-old vehicle

I am experiencing auto braking when there are no obstructions near or around the vehicle. The auto braking is random but occurs fairly often. It is very unsettling and makes me very nervous while driving my brand new vehicle. This happens without warning and can definitely put myself and my passengers as well as passengers in the vehicles around me at great risks of collisions.

Attention Assist System Suspended notification comes on randomly on vehicle while driving, rendering driver defenseless with regard to safety warnings that would otherwise be in effect, such as blind spot assist, attention assist, which are vital components for safe driving. This has happened on numerous occasions, most recently on 12/06/2024 while driving under destination route guidance. It has also happened when car was stopped to retrieve mail at residence mail box and, at other times for no apparent reason, while driving. Each time when engine was restarted the dashboard read 'System suspended' and continued to do so until car was returned to dealer. This vehicle was purchased on 12/21/2023 and with less than 350 miles began repeated problems with warnings, the first of which was "Check engine"on 02/02/2024, as car was running rough. Car was repaired(dealer determined cause was electrical/software error, fault code) yet before driving out of the dealership the same 'check engine' warning reappeared and vehicle had to be returned to service that same day for the same problem. Since that date in 2023, this vehicle has had numerous seemingly computer related issues that render it unreliable as to the safety devices this vehicle features that should always be maintained. On 03/21/2024 with less than 950 miles the fans remained running after shutting vehicle off and a message appeared stating" cooling system malfunction/reduced drive performance" with a red triangle on dashboard. Dealer determined the cause was 'SOFTWARE" At this point I am concerned that this vehicle is over engineered with computerized options that randomly fail. On another occasion the lights on one side may have been on overnight. The lights (courtesy lights) were on on the right side overnight in garage. My safety is continuously at risk whenever a warning appears.I replaced my GLK specifically to have Blind Spot Assist, PRE-safe, Attention Assist, Active distance assist and other features.

When driving the car at night with the headlights on, you notice a dark, thin object illuminated from the left front headlight approximately 50-75 feet ahead of the vehicle that will move as the steering is turned, either left or right. It looks like a thin pedestrian moving into the path of the car. I noticed this defect within the first few weeks of ownership. I took the car to the dealership and showed my pictures of the lights with the shadow at night to two Mercedes Benz of Sarasota employees. The dealership ran multiple diagnostic tests and determined the car was operating as designed. While the dealership had my car, two employees at the dealership noted they had relatives who had 2024 Mercedes Benz vehicles and had noticed this same issue. They also received the same explanation that this was the design of the headlights. It is concerning, as it could cause a driver to swerve or otherwise create an issue that leads to an accident. I request NHTSA look into this headlight issue and encourage Mercedes Benz to fix this before an accident happens. I have uploaded the work order documents from the dealership. I have uploaded a picture of the shadow reflected on a car ahead of me to show the shadow up close.

I purchased the car brand new from my local dealership and 3 months after purchase my windshield cracked. I had the entire windshield replaced with an OEM windshield on 5/7/2024 and yesterday I got another chip/crack in my windshield. I have only had my car less than 8 months and already had 2 cracks/chips. I owned my previous Mercedes over 6years and never had an chip or crack. This has to be a defect in the windshield. My friend also just purchased a 2024 GLC 300 and it's only 3 months old and her windshield is also cracked. I look forward to hearing from you.

Passenger backseat seatbelt would not release under any circumstance. I tried turning the car off and on again. Checking settings on the screen and even releasing the seat a bit. Pushing the red button on the buckle did nothing. Pulling did nothing. Eventually had to cut the seatbelt to get the passenger out. And it is still stuck in the buckle.

The contact owns a 2024 Mercedes Benz GLC 300. The contact stated that while attempting to park, the vehicle experienced unintended acceleration causing the contact to lose control of the vehicle and crash into a wall, another vehicle, and two poles where it came to stop when crashing into the second pole. During the unintended acceleration, the contact depressed the brake pedal to control the vehicle however it failed to respond. No air bags deployed. The contact sustained chest, neck, and back injuries and an ambulance transported her to a hospital. A police report was filed. The vehicle was towed to an independent mechanic by the insurance company. The vehicle was not repaired. The dealer was not contacted. The manufacturer was not made aware of the failure. The failure mileage was approximately 97,000.