2019 Mercedes-Benz GLC 300 Owner Complaints

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.

NHTSA ID

11736351

Incident

Apr 16, 2026

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.

NHTSA ID

11729435

Incident

Apr 5, 2026

Mileage

106,706 mi

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.

NHTSA ID

11728476

Incident

Mar 31, 2026

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.

NHTSA ID

11726943

Incident

May 1, 2025

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.

NHTSA ID

11721035

Incident

Feb 27, 2026

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.

NHTSA ID

11716844

Incident

Dec 30, 2025

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.

NHTSA ID

11714225

Incident

Aug 11, 2025

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.

NHTSA ID

11700738

Incident

May 21, 2025

Mileage

60,000 mi

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.

NHTSA ID

11682374

Incident

Aug 16, 2025

Mileage

48,000 mi

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.

NHTSA ID

11680728

Incident

Jul 27, 2025

Mileage

30,000 mi

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.

NHTSA ID

11680717

Incident

Aug 14, 2024

Mileage

63,500 mi

While driving on Route 95 the Front Stationary Sunroof Panel separated and flew off

NHTSA ID

11676892

Incident

Jul 28, 2025

FIRE! NHTSA Vehicle Safety Complaint – Mercedes-Benz GLC300 Complainant Information: [XXX] [XXX] Phone: [XXX] Email: [XXX] Vehicle Information: 2019 Mercedes-Benz GLC300 4MATIC VIN: [XXX] Purchase Location: Missouri Incident Location: St. Louis, MO Date of Incident: [XXX] Date of Report Submission: July 12, 2025 Summary of Incident: On [XXX] , my 2019 Mercedes-Benz GLC300 4MATIC spontaneously caught fire while parked. I immediately contacted Mercedes-Benz Roadside Assistance, and the vehicle was towed for inspection. Mercedes-Benz later claimed the fire originated in the engine compartment, yet took no accountability and cited “missing components” as an excuse to avoid liability. Photographic evidence shows that the parts were present immediately after the fire. Mercedes-Benz denied that NHTSA Recall 21V961000 applied to this vehicle, despite clear similarity in symptoms (fire risk due to fuel or electrical issues). I was also never notified of any fire risk. Furthermore, towing coordination failures led to my vehicle being sent to a third-party lot, incurring unauthorized fees. Safety Concern: The spontaneous combustion of this vehicle presents a serious public safety risk. I am concerned this issue may be more widespread and underreported. Mercedes-Benz’s failure to take accountability and deflecting blame could endanger other consumers. Desired Action: 1. Federal investigation into similar fire-related complaints involving 2019 GLC300s. 2. Reconsideration of eligibility under Recall 21V961000 or related campaigns. 3. Consumer safety alert or expanded recall if defect patterns are confirmed. Attachments Provided: - Mercedes-Benz USA denial letter dated July 11, 2025 - Photos of the fire damage - Letters and written communications Signature: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11672995

Incident

May 22, 2025

- My transmission is malfunctioning. It is available for inspection. - My car is not allowing me to shift from reverse to drive. When I try to put it in drive, it gets stuck in neutral. My safety is at risk as I was trying to do a quick 3-point turn and got stuck in the lane. - Yes, the problem has been confirmed by an independent service center. There was a recall by Mercedes Benz for the same issue in 2020, but for some reason my car isn't included. - The vehicle has been inspected by an independent service center - No warning lamps or messaged prior to the failure which first appeared on Thursday, June 5.

NHTSA ID

11666765

Incident

Jun 5, 2025

On May 22, 2025, while parked, my 2019 Mercedes-Benz GLC300 spontaneously caught fire, completely destroying the vehicle. Thankfully, no one was inside, and no injuries occurred, but the property damage was significant. I later discovered Recall 21V961000 / Campaign 2022030003 affecting some 2019 GLC300s for fuel leaks at the fuel rail/injector interface, which pose a serious fire hazard. Further research has shown reports of loose ground connections in these vehicles as well, increasing the risk of sparks igniting leaked fuel. Given that my vehicle caught fire spontaneously and matches the defect described in this recall, I firmly believe this incident was related to that defect. Mercedes-Benz has not provided adequate assistance. The vehicle was towed to a local dealership (Plaza Mercedes-Benz), but they refused to accept it, adding further confusion and hardship. I am submitting this report to request that NHTSA fully investigate this issue and work to ensure that Mercedes-Benz USA takes responsibility for this vehicle defect and compensates me for this dangerous failure. I am happy to provide photos, tow reports, or further documentation if needed. Thank you for your assistance in ensuring public safety.

NHTSA ID

11666424

Incident

May 22, 2025

Faulty Positive Crankcase Ventilation Valve. Seems a very common failure which causes poor emissions and potentially further engine damage.

NHTSA ID

11650016

Incident

Mar 23, 2025

The component that failed was the right front differential. My safety and the safety of others was put at high risk as I was driving at 60 mph on the highway and my vehicle suddenly and abruptly reduced speed to about 15mph without any warning. This created an extremely dangerous and potentially hazardous situation as I tried to maneuver my car at this very low speed on the highway in the middle lane safely to the side of the highway. Cars around me quickly maneuvered around me in attempts to avoid my slow moving vehicle and not hit me. The entire experience was terrifying, especially given that the car gave no prior indication of a malfunction. The vehicle had to be towed to Mercedes. I have no real answers from Mercedes as to the cause or why the vehicle did not notify me or why the service light did not go on. The vehicle only had 51,000 miles and is well taken care of. Because the car was out of warranty they refused to cover the expense. I called and sent letters to corporate and received $2500 towards a $6000 bill. I feel this was a safety issue and my car shut down without any type of warning and Mercedes should cover all repair costs. The car has been repaired, but I am still nervous to drive it.

NHTSA ID

11641513

Incident

Jan 9, 2025

Sunroof exploded while I was driving. No other cars around me, pretty day, not a very hot day. I’m driving along and suddenly hear a loud POP that sounded like a shotgun going off! I swerved, but thankfully did not leave the road. Shattered glass was contained in the cover of the sunroof as I didn’t have it open at the time. A huge hole is in my roof of my car! I called the dealership who said it was not covered under any warranty although I just got the vehicle in Feb of this year. He said I would have to contact corporate. I contacted corporate who said bring it in for an inspection. At the conclusion of the inspection on 10/8/24, they could not determine if it was a manufacturer defect or outside sources since they could not find a point of impact, because the glass was nearly all gone. I had to get my insurance involved. There was no warning whatsoever. The dealership said no recalls. It just exploded all of a sudden!

NHTSA ID

11618779

Incident

Oct 2, 2024

The contact owns a 2019 Mercedes-Benz GLC300. The contact stated that the tires were worn in one specific area and the failure had also occurred after replacing the tires. The contact took the vehicle to the dealer where an alignment was completed; however, it was confirmed that the rear hub bearing was rubbing the tires and needed to be replaced. The vehicle had not been repaired. The manufacturer was not made aware of the failure. The failure mileage was 79,000.

NHTSA ID

11611131

Incident

Jan 27, 2023

Mileage

79,000 mi

The contact owns a 2019 Mercedes-Benz GLC300. The contact stated while driving at an undisclosed speed, the contact heard an abnormal sound emanating from the vehicle from an unknown location. The contact pulled over to the shoulder of the roadway and after a visual inspection of the exterior of the vehicle, the contact observed that the front roof panel had become detached. The vehicle was not taken to the dealer or an independent mechanic. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 23V854000 (Structure) but the VIN was not included. The manufacturer was notified of the failure but referred the contact to the NHTSA Hotline for assistance. The failure mileage was unknown.

NHTSA ID

11594442

Incident

Jun 13, 2024

The error code is P052E and it is a PCV Code Crankcase Ventilation Oil Separator. It's a time-consuming and expensive repair that seems to be regularly occurring on a lot Mercedes Benz that have this installed. And it happens often on cars with under 50K miles on them and when it's just been out of warranty this is a small inexpensive part that the customer funds through the cost of labor. Not that mechanics don't deserve their labor costs, but Mercedes ought to fix this is issue as it is borne by the consumer of a high end vehicle for a consistent, faulty part that they have engineered.

NHTSA ID

11589246

Incident

May 2, 2024

The four tires were replaced on [XXX] at 28,000 miles. Then 4 additional tires replaced at 57,000 miles [XXX]. Less than one year in Oct of 2023 I noticed a sound coming from the front tires when driving . Two of the front tires needed to be replaced 75300 miles . These tires FPIRREILLI SCROPION VERDE 235/55 R19 101H are having to be replaced too often . There appears to be a defect in the tires INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11587477

Incident

Nov 20, 2023

The contact owns a 2019 Mercedes-Benz GLC300. The contact stated while driving 25-30 MPH in the rain, the front driver's side window became foggy, and the front driver's side window power switch button was depressed to roll down the window to clear the fog; however, the switch fractured in her hand. The manufacturer was notified of the failure and a case was opened. The manufacturer referred the contact to the dealer for assistance. The dealer was contacted. The vehicle was not diagnosed or repaired. The manufacturer later informed the contact that they could not help. The failure mileage was approximately 27,500.

NHTSA ID

11582221

Incident

Mar 23, 2024

Mileage

27,500 mi

P052E71 Engine Separator and actuator malfunctioning. Was told this fails several times on Mercedes vehicles. I will not pass emissions with this issue. Over $2K to repair and engine light along with code appears. I have videos of the engine light coming off and on. Car has been inspected by Firestone and Mercedes Service Center.

NHTSA ID

11572879

Incident

Jan 25, 2024

We hit a deer at 50mph. Active restraint system pulled us back into our seats. Cabin filled with white smoke/powder. Windows automatically lowered a few inches. Dash display panel issued fault alarms on all airbags and emergency braking systems; front and rear. Vehicle automatically contacted Mercedes SOS and dispatched police. Air bags never deployed.

NHTSA ID

11571313

Incident

Feb 9, 2024