2020 MERCEDES-BENZ GLC 300 Complaints

My check-engine light recently illuminated, and diagnostic testing identified fault code P06DA00, relating to the oil pump control valve circuit. I have been quoted over $5,000 to replace the oil control valve and oil pump harness. I was quoted the following by Mercedes Servuce in Manchester, NH- Oil Pressure Regulator Valve: need to remove lower oil pan only to access oil control valve and replace the valve and sub harness. $5013.52. This is a known issue. My vehicle has been well maintained, and I have been advised that it is otherwise in excellent mechanical condition. I intend to keep and drive this vehicle for many more years, which makes it particularly disappointing to encounter a repair of this magnitude for a component that is not considered a routine maintenance or wear item.

What component or system failed or malfunctioned, and is it available for inspection upon request? The Forward Collision Avoidance / Active Brake Assist (Automatic Emergency Braking) system failed by falsely identifying a non-existent threat and initiating uncommanded emergency stopping. The vehicle and its onboard control modules are fully available for physical and diagnostic inspection upon request. How was your safety or the safety of others put at risk? While traveling at approximately 35 mph, the vehicle suddenly executed maximum emergency braking with zero warning and no preceding obstacles, vehicles, pedestrians, or road hazards present. The violent deceleration caused maximum seatbelt restraint locking force, resulting in sudden physical impact trauma to a 6-month pregnant passenger and acute dizziness/disorientation for both occupants. This malfunction creates a severe, immediate risk of high-speed rear-end collisions from trailing traffic and unexpected loss of vehicle control. Has the problem been reproduced or confirmed by a dealer or independent service center? Not yet. The vehicle has not yet been serviced or inspected by a dealer or independent service center following this event. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? No. Neither the manufacturer, police, insurance representatives, nor third-party investigators have inspected the vehicle or component since the incident occurred. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? There were no warning lamps, error messages, chime alerts, or functional symptoms prior to the sudden brake activation. The Active Brake Assist system triggered immediately without prior warning.

My 2020 Mercedes-Benz GLC 300 triggered check engine light with code P06DA (engine oil pressure control) at 40,000 miles. The failed component is an oil pressure control sensor/solenoid worth approximately $200. However, due to Mercedes-Benz's engine design (M264 engine), the entire engine must be removed from the vehicle to access and replace this part. Repair estimate from authorized Mercedes-Benz dealership (Mercedes-Benz of Stevens Creek): $8,391. SAFETY CONCERN: Loss of oil pressure can cause catastrophic engine failure while driving. Engine seizure at highway speeds poses serious risk of loss of vehicle control, potential accident, and harm to occupants and other drivers. This is a known, widespread design defect affecting Mercedes-Benz vehicles equipped with M264/M274 engines across multiple model lines: GLC 300 (2019-2023) C 300 (2019-2023) E 300 (2019-2023) GLC 43 AMG, C 43 AMG GLB 250, A 220, CLA 250 Mercedes-Benz's own authorized dealership confirmed they are "seeing this issue more and more." Despite awareness of this widespread defect, Mercedes-Benz has not issued a recall or Technical Service Bulletin. The design makes repair financially prohibitive ($8,000+), meaning many owners continue driving with compromised oil pressure — creating an ongoing safety hazard on public roads. Mercedes-Benz refused to repair under goodwill, then denied repurchase after 30-day review. They have left consumers with no remedy for a known safety-related design defect. I am requesting NHTSA investigate this as a safety defect affecting potentially hundreds of thousands of vehicles.

I have had my car for almost two years. This problem has been on-going the whole time. It happens intermittently, I never know. I will be driving it and usually when I am making a turn or pulling onto a main road, you press the gas to go and the car hesitates and makes a loud brooooooooom sound like it is trying to go or figure out what to do and if you are pulling out onto a main road with on comming traffic, this is dangerous. We have seen information that on the 2019 and 2018 GLC300's this has been documented, my car is a 2020 but it's the same thing. It's like the car hesitates and slows down when it should go!

There was a recall on headlight leaking and this happened to my left headlight no damage but leaking and this caused headlight to not work

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated that while driving at an undisclosed speed, the panoramic roof unexpectedly shattered. There was no warning light illuminated. The vehicle was taken to the dealer, where it was determined that the panoramic sunroof and the sunroof protector needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure, and a case was opened. The approximate failure mileage was 53,035.

Premature oil pump failure on a 2020 Mercedes-Benz GLC 300 with 71,000 miles. The check engine light illuminated on December 29th, 2025 and with no other warning symptoms. The vehicle has been maintained properly, including regular visits to Mercedes-Benz dealerships. The oil pump is a critical engine component that should not fail at this mileage. It has been recommended to not drive the vehicle without repairing as oil can leak onto a hot engine. This issue has been confirmed by a Mercedes dealer. Mercedes-Benz has offered $1,000 in goodwill on a $7,400 repair, which is unreasonably low given the nature of the failure. The dealer is advocating for higher goodwill, but corporate has refused to escalate or provide a breakdown of the offer. This failure appears to be a premature mechanical defect rather than normal wear, and I am filing this complaint to request federal tracking and review.

Water condensation within the driver side headlight which caused the complete headlight unit, control unit, and module to fail. This is a huge safety issue due to unable to operate vehicle safely during the when it comes to making left turns due to no signal indicator and a safety issue/hazard when driving at night. The issue has been inspected with a local dealer and with corporate being aware of the manufacturer defect. There were no indicators nor warning lamps prior to this issue.

The front main light on the driver side stopped working after a rain and it continued getting moister in the head lamp every night until a few days ago and as a result the head light assembly does not work at all ,the same thing is happening on the passenger side front head light assembly except it is still working .research showed that this has been a problem on similar Mercedes Benz cars and considering that the car has not had any accidents to possibly causing this it was concluded that this should have been part of the recalls .car is not operatable and i reached out to Mercedes Benz and they acted like I am out of my mind and it is passed the express warranties with car having 69000 miles. I tried explaining to them about the implied warranty and the safety problem and they continued with the same none sense. at this point The MBZ dealers want over $ 6000.00 to replace the part and I am not able to operate car.what can you do for me and others effected.

The engine in my 2020 Mercedes-Benz GLC 300 suddenly malfunctioned while driving on two separate occasions. The vehicle began shaking violently and lost power without warning. I could not accelerate and had to pull over immediately. I turned the vehicle off and restarted it to regain limited driveability. On the second incident, the power loss was so abrupt that it felt as if I had been rear-ended. I feared the vehicle would stall in traffic and cause a crash. Following these events, the check engine light remains constantly on. The dealer inspected the vehicle and confirmed excessive valve leakage into the exhaust system, requiring a complete cylinder-head replacement. They warned the failure will worsen and could result in sudden power loss again. This defect poses a serious safety risk. If the power loss occurs while merging or at highway speeds, it could easily lead to a rear-end collision. The vehicle has relatively low mileage for such a severe internal engine failure, and I have learned that other owners of this same engine have reported similar issues. Sudden stalling or loss of acceleration places occupants and other drivers in danger. There were no warning messages prior to the failure, and the problem has recurred. The vehicle is available for inspection, and the defect has been confirmed by a Mercedes-Benz service center. This appears to be a mechanical defect in the engine design, potentially involving valve seat failure. An investigation is needed to determine if this issue is widespread and whether a recall or manufacturer action is required to prevent accidents or injuries.