2019 Mercedes-Benz GLC-CLASS Coupe

On April 16, 2026, within minutes of being released from a certified dealership, my 2019 Mercedes-Benz GLC 300 suffered a sudden and total loss of propulsion while traveling at high speed on the Belt Parkway (NY). Despite depressing the accelerator, the vehicle failed to maintain speed and stalled in active traffic. This created an immediate life-safety hazard, forcing me to navigate across multiple lanes without engine power to avoid a high-speed rear-end collision. The vehicle was released to me by Mercedes-Benz of Brooklyn on April 16, 2026, following a repair for which I paid $2,134.94. The dealership diagnosed the issue as a wiring harness/sensor fault and formally certified the vehicle as "Found OK" and safe for operation. The catastrophic failure occurred only 22 minutes after I departed the dealership lot. The vehicle had to be towed back to the facility immediately. Upon the vehicle being towed back on April 16, the dealership admitted via recorded voicemail that the initial $2,134.94 repair was a misdiagnosis. They subsequently issued a new diagnosis for a "Valve Body" failure and a new quote of $6,424. The dealership's Service Director has since admitted the vehicle suffers from concurrent transmission and engine failures, rendering the car a liability. This represents a critical failure of the powertrain and electronic control systems. Releasing a vehicle that suffers a total power loss on a highway immediately after a "certified" repair is gross negligence. I am reporting this to NHTSA as a catastrophic failure of a safety-critical component (Transmission/Valve Body) that resulted in a "dead-stick" situation on a major New York thoroughfare, posing a severe risk to myself and other motorists. The vehicle remains at the dealership. Mercedes-Benz USA has offered only a $2,000 "goodwill credit," which does not address the safety defects or the initial misdiagnosis. No recall has been initiated for this batch.

The contact owns a 2019 Mercedes-Benz GLC300. The contact stated that while driving 65 MPH on the interstate, the sunroof suddenly shattered into pieces and flew off the vehicle. The vehicle was driven to a dealer but was not repaired. The manufacturer was notified of the failure. The failure mileage was 106,706.

I have a MC Benz 300 GLC with $50,000 miles. I was having heating issues so took it to the dealership, which basically advised of the issue describer below, which would cost $14k to repair. Contaminated coolant in Mercedes-Benz GLC 300 models often results from the internal failure of a "desiccant bag" inside the coolant expansion tank, which disintegrates, releasing material that clogs the heater core. Symptoms include black residue in the tank, reduced cabin heat, and engine overheating. Key actions include replacing the expansion tank (reservoir) and flushing the entire system.

A message that passenger air bag is damaged/will not deploy appears. Passenger seat belt gets stuck and cannot be opened. Check engine light on-pvc valve issue most likely.

SUNROOF EXPLODED AND SHATTERED. I HEARD IT WHILE DRIVING AND HELD ON TIGHTLY TO THE STEERING WHEEL BEFORE I REALIZED WHAT IT WAS. THE DEALER AND MY AUTO INSURANCE HAVE BEEN CALLED, NEITHER PICKED UP, AND I LEFT EACH A VOICE MAIL MESSAGE. NO WARNING LAMPS, MESSAGES OR OTHER SYMPTOMS OF THE PROBLEM OCCURRED.

My sunroof just exploded while driving on the highway without any impact or warning. It was a clear sunny day. There wasn't a vehicle in front of me. Nothing fell on my windshield nor sunroof. The sudden explosion and shattering of the glass was extremely startling. I had a mesh underneath the sunroof that contained some of the shattered glass so it did not fall on me while I was driving. I'm so thankful there wasn't a car behind me for the glass debris to fall on. Mercedes USA was not helpful, unresponsive for many weeks. They eventually declined repair coverage due to out of warranty, not manufacture defect nor safety issue.

I was driving on a street 5mph and all of a sudden my car surged and led me to curb where i knocked hit a steer din and it veered onto someone’s lawn and hit a huge planter and stopped . Air bags were deployed . I had no control over the car . EDR was preformed and I’m sure it was a throttle surge issue and cause unintended acceleration . The edr shows I was going 5 miles an hour but then says pedal was pushed to 100%. While traveling at approximately 4–5 mph during a low-speed maneuver, with light accelerator input, the vehicle unexpectedly surged forward. I did not intend to accelerate. The vehicle rapidly increased speed, left the roadway, struck a street sign and a planter, and the airbags deployed. Event Data Recorder (EDR) data retrieved by the insurer (Mercury Insurance) shows the vehicle traveling at low speed immediately prior to the event, followed by a recorded 100% accelerator pedal position. This data does not reflect my driving intent and appears inconsistent with the low-speed conditions. The EDR documentation notes that accelerator pedal position is sampled asynchronously and reflects values transmitted to the SRS Control Module, not continuous pedal input or driver intent. No brake input was recorded prior to the impact. The sudden acceleration occurred too quickly to react. Mercedes-Benz inspected the vehicle and released only the EDR data, declining to provide further clarification regarding throttle control logic, pedal sensor correlation, or torque command behavior. I am reporting this incident due to concern that low-speed throttle control behavior, software logic, or transmission engagement may result in unintended acceleration without corresponding driver intent, posing a safety risk during parking-lot or low-speed driving conditions.

The contact owns a 2019 Mercedes-Benz GLC300. The contact stated that while shifting from reverse to drive, the vehicle stalled and remained in neutral. After the vehicle stalled, the vehicle took approximately 8 minutes before the vehicle could be shifted into drive. Once in drive, the vehicle would jerk and shift to D3 before accelerating. The check engine warning light would illuminate while in reverse. The vehicle was taken to the dealer, who diagnosed a transmission failure due to a malfunctioning valve body and low pump pressure. The dealer confirmed that the VIN was not under recall and that the issue was not covered under warranty. The vehicle was not repaired. The contact informed the manufacturer of the failure, and a case was opened. The manufacturer referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 60,000.

The contact owned a 2019 Mercedes-Benz GLC 300. The contact stated that while driving at 15 MPH up and down the street on the fourth trip, the vehicle pulled to the left and suddenly accelerated, traveled over the curb, went through a sign on a pole, vegetation, and crashed into a concrete planter box. There were no warning lights illuminated. The air bag deployed. The contact sustained bruises on her knees and hands. Medical attention was provided at the hospital. The paramedics, the police department, and the fire department were on the scene. The paramedics checked her out at the scene. There were no reported fires. A police report was filed. The vehicle was towed to a tow lot. The local dealer was not contacted. The vehicle was not diagnosed or repaired. The contact was working with her insurance company to obtain the black box. The vehicle was deemed a total loss by the insurance company. The manufacturer was not contacted. The failure mileage was 48,000.

Engine runs rough and activates a flashing engine light. Sounds like the engine is misfiring. On two occasions the engine stalled,(no power steering, brakes...) luckily not in a dangerous situation. No engine codes were visible to a technician when try to diagnose. Car seemed to run fine again after restart.

The contact owns a 2019 Mercedes-Benz GLC300. The contact stated that while stopped at a stoplight on a hill, the vehicle rolled backwards. The contact stated that the brake pedal was depressed to stop the vehicle from rolling backwards, preventing the vehicle from hitting the vehicle behind. The contact stated that the failure had occurred several times. The vehicle was taken to the dealer; however, the failure was not duplicated. The contact was informed that rolling backwards was normal. The manufacturer was not made aware of the failure. The failure mileage was approximately 63,500.

The contact owns a 2019 Mercedes-Benz GLC 300. The contact stated that while driving 60 MPH, there was an abnormal cracking sound coming from the roof. The contact stated that upon arriving to the destination and parking the vehicle, the contact became aware that the panoramic roof panel had detached. The dealer was notified of the failure. The vehicle was not repaired. The contact related the failure to NHTSA Campaign Numbers: 23V854000 (Structure) and 21V197000 (Structure). The manufacturer was notified of the failure and informed the contact that the VIN was not included in the recalls, and assistance could not be provided because the vehicle was out of warranty. The failure mileage was approximately 30,000.