What 61 owners told NHTSA about the 2021 Mercedes-benz GLC Coupe

The vehicle lost power and will not operate over 40 mph/2000 rpms

NHTSA ODI 11697192

High beam can't auto dim Fuel pump fail to operate, misfires, and shut down while driving

NHTSA ODI 11646060

The contact owns a 2021 Mercedes-Benz GLC300. The contact stated that while driving at low speeds, the vehicle lost motive power struggling to produce enough power to propel itself on a slight incline. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the fuel pump. The vehicle was not repaired. The vehicle was then towed to the dealer, who confirmed the diagnosis. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA campaign 23V880000 (Fuel System, Gasoline), but the VIN was not included. The manufacturer was notified of the failure; a case was opened, and the contact was referred to the NHTSA hotline for assistance. The failure mileage was 80,000.

NHTSA ODI 11628817

Vehicle has a known engine failure. Leaking valve in Cylinder head. Cylinder 3 injector is faulty

NHTSA ODI 11618196

The contact owns a 2021 Mercedes-Benz GLC300. The contact stated that while his wife was driving in the rain approximately 35 MPH, the vehicle lost motive power and stalled. The vehicle was able to be restarted. The vehicle was taken to a dealer to be diagnosed. The contact was informed that the cylinder head needed to be replaced. The vehicle was repaired but the failure reoccurred. The contact believed that the failure was associated with NHTSA Campaign Number: 23V445000 (Fuel System, Gasoline) however, the VIN was not included. The manufacturer was notified of the failure. The failure mileage was 19,369.

NHTSA ODI 11567062

This is the 3rd incidence of this issue (July, Oct, Dec), but we have been advised that a software update is not yet available from the manufacturer. In all instances, we were travelling at a normal rate of in-city traffic (30-45 mph) and all of sudden the vehicle will not accelerate above 25 mph regardless of the position of the throttle. My dealer, Mercedes Benz of Tampa, advises that the problem can only be corrected permanently with a "software update" which is not yet available. This is a major safety issue, especially on the highway, as the vehicle could suddenly and unexpectedly be unable to accelerate, in fact, decelerates at random times without warning.

NHTSA ODI 11559715

The contact owns a 2021 Mercedes-Benz GLC300. The contact received notification of NHTSA Campaign Number: 23V445000 (Fuel System, Gasoline) however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure. VIN tool confirms parts not available.

NHTSA ODI 11558908

My car was bought new in October 2021 & I began having problems after having it for 6 months & the mileage at that time was about 4000 miles - it was in April 2022 & the check engine light came on & I had a loss of power to where it slowed down & would not go any faster than about 30/35 miles an hour going on a straight road way & no faster than about 10 miles an hour going uphill. The engine sounded funny as well. It had to be towed to the dealership for repair. This incident happened again a month later & it was towed to the dealership at that time. The next incident just happened this month (mileage=6620) & again it was towed to the dealership for repair. Same scenarios all 3 times. This last incident, I was told that it is glitch & they don't really know what is causing my car to basically go into "limp mode"; however, they are awaiting a software update that they expect will resolve the problem, but they are not sure when it will be available for installation & did not give me a timeline. In the meantime, I was given back my car as I was the 2 other times without a resolution or security that my car is doing to make it to & from my destination. The car is still under warranty & just under a year old now. I was told by the dealership that they have no other customers complaining of this problem & they feel it is very isolated. I asked them to reach out to their corporate office in hopes of making a deal with me as I have lost all confidence in the car, but they reported having no luck in reaching anyone to discuss my problem. The 3 incidents where the car had to be towed were very scary for me as other cars were blowing their horns at me because I could not accelerate & go any faster & when I was going up a hill - it was really bad. I was very lucky that all 3 times happened not far from my home & not on the interstate as the outcome could have been very bad for me in regards to my safety.

NHTSA ODI 11486730

Entered parked vehicle and noticed very strong gas fumes. Vehicle would not start. Looked under the vehicle and noticed very large quantity of gasoline on the ground. Vehicle was towed to Mercedes dealership in Rochester, Michigan. Diagnosis was an incorrectly installed fuel line bracket. New bracket was installed and problem was corrected.

NHTSA ODI 11421457

Fuel line malfunctioned, car stopped , gasoline was pouring out from under the hood. I was "lucky" that it did not catch fire, fire department showed up, closed the street, car was towed, dealership " replaced high-pressure line of fuel system high pressure pump". It all started without a warning, suddenly after about 1 month of driving ( 1000 miles) a brand new Mercedes GLC300.

NHTSA ODI 11421117

ON APRIL 21, 2021 AT ABOUT 1800 (TIME), LESS THAN 45-HOURS AFTER PURCHASE OF THE NEW 2021 GLC 300 VEHICLE, THE INTERNAL COMBUSTION (ENGINE) MISFIRED AND ABRUPTLY MALFUNCTIONED WHILE IN STEADY ACCELERATION AT 65-MPH. MY FAMILY AND I WERE HEADED EASTBOUND ON THE CA-60 FREEWAY IN LANE THREE (LEFTMOST, FASTEST LANE). AS SOON AS THE ENGINE SPONTANEOUSLY SPUTTERED, IT ABRUPTLY STOPPED AND INTENSELY SHOOK THE ENTIRE CAR VIGOROUSLY, AGGRESSIVELY, AND CONTINUOUSLY WITH NO ABILITY FOR CONTROL NOR FOR THE OPTION TO CONTINUE TO ACCELERATE. THERE WERE THREE CARS BEHIND MY VEHICLE ALSO ACCELERATING AT THE SPEED OF TRAFFIC (65-MPH) THAT ALSO ABRUPTLY SCREECHED TO A HALT TO STEER CLEAR OF MY UNUSUALLY MALFUNCTIONING VEHICLE. THIS WAS THE MOST TRAUMATIC EVENT THAT HAS EVER HAPPENED TO MYSELF AND MY FAMILY IN OUR LIFETIME. AS YOU CAN IMAGINE, WE FEEL EXTREMELY FORTUNATE IN HAVING SURVIVED THIS HORRENDOUS, UNEXPECTED, AND CRUEL SAFETY RISK AS NO COLLISION WAS FORTUNATELY REPORTABLE. THE VEHICLE'S MALFUNCTIONING AND PERFORMANCE ISSUE HAD PLACED US IN AN EXTREMELY HIGH-RISK OF SAFETY CONCERNS AND NEAR MOMENTS FROM MY OR MY FAMILY'S HEALTH-RELATED TRAGEDY AS THE HALT OF NUMEROUS CARS WITHIN THE FREEWAY CLOSELY SWERVED-AWAY FROM OUR DIRECTION. AS YOU CAN IMAGINE, WE ARE SEVERELY, PHYSICALLY, EMOTIONALLY, AND MENTALLY DISTRAUGHT DUE TO THE MANUFACTURING DEFECT TO THE 2021 GLC 300 ENGINE. AFTER 30-HOURS OF CONTINUED QUESTIONING, ANALYSIS AND DISCOVERY, IT WAS CONFIRMED OF VALVE TRAIN COMPONENT DEFECT CAUSING MAJOR DOWNSTREAM EFFECTS TO THE ENGINE AND IMMEDIATE INABILITY TO ACCELERATE ON THE HIGHWAY WITH DIRECT SERIOUS LIFE THREATENING RISK TO A NEW VEHICLE AND MY FAMILY WITHIN IT. PLEASE CONSIDER THIS DETRIMENTAL INCIDENT FOR OTHER'S GLOBAL SAFETY THROUGH MY TRAGIC EXPERIENCE.

NHTSA ODI 11413885