2020 Mercedes-Benz GLC 300 Problems

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!

The engine is failing, I was on my way to drop my [XXX] off at daycare when suddenly my car went above and stayed above 5rpms meanwhile I was only able to drive 8mph. This caused a tractor trailer swerving into on coming traffic, if he didn’t my toddler and I would have been killed. As I managed to pull off and call my husband to get the baby the engine started making a strange clicking noise. There’s maybe 60,000 miles on this vehicle none of this should be happening. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

On August 15, 2025, I was driving my Mercedes-Benz GLC 300 4MATIC on the freeway under normal conditions. Without any warning lights, error messages, or prior signs of mechanical issues, the vehicle suddenly and completely lost power. The accelerator pedal became unresponsive and felt locked, and the vehicle came to an abrupt stop in the middle of an active freeway, in the second lane from the left. I had no ability to control or prevent the stoppage. This unexpected power loss directly led to a rear-end collision. The vehicle behind me sustained severe front-end damage, including airbag deployment. My passenger and I were in shock and suffered whiplash and physical injuries, with pain and bruising following the impact. I suspect the most likely causes may be an Electronic Throttle Control failure or a false activation of an Active Safety System. I opened a case with MBUSA (Case #16298894) immediately after the incident, but I have not received any updates on the investigation. This was a dangerous and life-threatening failure, and I am deeply concerned that it could occur again to other drivers if not addressed.

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

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.

Center COMAND screen malfunctions. No rear camera view when reversing when screen does not work. Dealer attempted a repair but issue remains. Parts ordered for replacement.

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated that while operating the vehicle, the 12-Volt battery warning light remained illuminated. The contact stated that while driving at various speeds, the vehicle shut off. The failure also occurred while driving on a busy freeway. The vehicle was towed to the local dealer who diagnosed that the STOP/START button was faulty and needed to be replaced. The STOP/START button was replaced but the failure persisted. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was 40,000.

The contact owns a 2020 Mercedes-Benz GLC300 equipped with Goodyear Tires, Tire Line: Eagle Sport All Season, Tire Size: 255/45/R20, DOT Number: NE12JU1R1021. The contact stated that within a year of purchasing the vehicle brand new, he noticed that there was significant amount of rubber coming off the outer side of the front passenger's side tire. The contact stated that the failure was moderate on the front driver's side tire. The contact stated that the vehicle was taken to the dealer, where the front driver's side tire was replaced twice due to the failure. Additionally, the front passenger's side tire was replaced three times; however, the failure persisted. The contact stated that upon investigating the failure online, he learned that the steering knuckle might be damaging the tires. The dealer was notified of the failure. The vehicle was not diagnosed or repaired. The vehicle and the tire failure mileage were approximately 6,000.

the power steering wheel adjustment stopped working, leaving the steering wheel stuck in a very unconfutable position for driving. The car just ended its 4 yr warranty

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!

Nationwide known cylinder head issues. Cylinder head work needing replaced.

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!

Panoramic sunroof blew off vehicle while driving. Other drivers were put at a risk from a vehicle component flying through the air at high speed. The vehicle has been inspected by the dealership. No warnings prior to the problem. There is a recall with Mercedes Benz for this issue buy my VIN is not the included number but should be included.

On Saturday October 5th at roughly 8:30 p.m. heading West on I-94 near battle creek, MI, the glass sunroof on our Mercedes suddenly exploded out and shattered. We were traveling at 75 mph with little surrounding traffic and no over-head obstructions. It took a second to re-gain control of the situation and slow down to a stop. We had the sun-shade closed, saving us from glass shards raining down from the exploded sunroof. The following Monday morning, Oct 7th around 9:00 a.m., we called Mercedes about the issue. They were indifferent and offered no assistance. They pointed out that our MY2020 with 29,711 miles on the odo was not covered under warranty for the sunroof shattering and that we would have to deal with our insurance company. They also informed us that they would not have any rental cars available during a repair until at least December. We mentioned that there was signs on the internet of class-actions against Mercedes for similar sunglass explosions to which they quickly responded with - not on MY20 300 GLC. We did get the sunroof replaced through our insurance. Anecdotely, when we took it into the glass repair shop, they had just did another one, similar situation the week before. This could have been tragic. Glass shards could have been everywhere. The only reason the sunscreen was deployed was that we had our baby granddaughter in the car only 1 hour earlier. Otherwise, that screen would have been open and the glass would have rained down on everyone in the car.

I have had issues with squeaky, very loud noises at slow speed and reverse braking. I have had this issue since I purchased this vehicle. I have brought it in a few times to have 2 different dealers fix the noise as I believe it is a safety issue as well. They said this is a common issue with GLC that they have noises while braking but there is no fix. I had an advisor drive the vehicle and witness loud squeaky noises while braking. Spending a lot of money on this vehicle, and Mercedes should fix this issue. I believe the brake system falls under lemon law and Mercedes should do something to mitigate the issue. The brake pads were okay upon inspection, but pretty soon I will have to pay a lot of money to replace pads at my own expense when the brakes, pads, rotors, etc themselves should be replaced and fixed at Mercedes expense.

The first day the car was picked up by us, we turned back and complained about the steering wheel and drivers' seat vibration. They checked it and we were told they cannot find anything. We were told to drive the car for awhile and return it if this complaint persists. We returned it to Okemos Mercedes with the same complaint. They said it is the tires and they replaced the right front tire. I told them I was driving since I was 17 and I know the difference between body and tire problems. We were told to try it again and come back and if it persists to return for diagnostics. Same response. I have complained to both dealership and and Mercedes main office and Mercedes does not agree it is a warranty issue. During the July 4th holidays, our son drove it and it was the first time I became a passenger. I cannot believe how scary the vibrations, noise and feeling unsafe in the back was. I made numerous calls to Mercedes and they keep pointing at the tires as the issue. The tires are supposed to have 2 more years tread left but Mercedes Okemos tried to sell us a tire. I was told by Mercedes main office to keep calling [XXX] at Okemos Mercedes service center but he had not returned calls. Mercedes main office said [XXX] had not returned calls, either. They were pointing fingers at each other while we were driving our grandchildren in an unsafe car. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated that while operating the vehicle, the air bag warning light remained illuminated, indicating that the front passenger’s side seat air bag was inoperable. The cause of the failure was not yet determined. The local dealer and manufacturer were notified of the failure, but no assistance was offered. The failure mileage was approximately 30,000.

The contact owns a 2020 Mercedes-Benz GLC300. The contact stated that upon driving through an intersection at 40 mph, another vehicle had run a stoplight. The contact swerved in an attempted to avoid the vehicle, however, she had hit the vehicle's rear driver side tire weld. The contact stated that the driver-side airbag did not deploy upon impact; however, the passenger-side airbag, where her mother was seated, did deploy. The Mercedes-Me app automatically called 911 and the contact initially declined medical attention at the time. A police report was filed. Due to the failure, the vehicle was towed to an independent mechanic. The next day, the contact was referred by her doctor to a hospital where they performed a cat scan and x-ray. The contact tested positive for Covid-19 the following Monday and believed it was as a result of the hospital visit. The manufacturer was notified of the failure and upon her own research, the contact discovered NHTSA Campaign Number: 21V354000(BACK OVER PREVENTION, ELECTRICAL SYSTEM). The vehicle remained in the possession of the independent mechanic and had yet to be repaired. The failure mileage was unknown.

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.

On Saturday October 5th at roughly 8:30 p.m. heading West on I-94 near battle creek, MI, the glass sunroof on our Mercedes suddenly exploded out and shattered. We were traveling at 75 mph with little surrounding traffic and no over-head obstructions. It took a second to re-gain control of the situation and slow down to a stop. We had the sun-shade closed, saving us from glass shards raining down from the exploded sunroof. The following Monday morning, Oct 7th around 9:00 a.m., we called Mercedes about the issue. They were indifferent and offered no assistance. They pointed out that our MY2020 with 29,711 miles on the odo was not covered under warranty for the sunroof shattering and that we would have to deal with our insurance company. They also informed us that they would not have any rental cars available during a repair until at least December. We mentioned that there was signs on the internet of class-actions against Mercedes for similar sunglass explosions to which they quickly responded with - not on MY20 300 GLC. We did get the sunroof replaced through our insurance. Anecdotely, when we took it into the glass repair shop, they had just did another one, similar situation the week before. This could have been tragic. Glass shards could have been everywhere. The only reason the sunscreen was deployed was that we had our baby granddaughter in the car only 1 hour earlier. Otherwise, that screen would have been open and the glass would have rained down on everyone in the car.

The first day the car was picked up by us, we turned back and complained about the steering wheel and drivers' seat vibration. They checked it and we were told they cannot find anything. We were told to drive the car for awhile and return it if this complaint persists. We returned it to Okemos Mercedes with the same complaint. They said it is the tires and they replaced the right front tire. I told them I was driving since I was 17 and I know the difference between body and tire problems. We were told to try it again and come back and if it persists to return for diagnostics. Same response. I have complained to both dealership and and Mercedes main office and Mercedes does not agree it is a warranty issue. During the July 4th holidays, our son drove it and it was the first time I became a passenger. I cannot believe how scary the vibrations, noise and feeling unsafe in the back was. I made numerous calls to Mercedes and they keep pointing at the tires as the issue. The tires are supposed to have 2 more years tread left but Mercedes Okemos tried to sell us a tire. I was told by Mercedes main office to keep calling [XXX] at Okemos Mercedes service center but he had not returned calls. Mercedes main office said [XXX] had not returned calls, either. They were pointing fingers at each other while we were driving our grandchildren in an unsafe car. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

There is a squeaky noise from the suspension, shock absorbers or somewhere in that area. They have fixed the issue multiple times. Kept my car in the workshop for days multiple times but it’s not getting fixed. They probably sold me a lemon. I need help in rectifying this issue.

The contact owns a 2020 Mercedes Benz GLC300. The contact stated that while driving at approximately 60 MPH, the front of the vehicle was vibrating and shaking violently. The vehicle was taken to the dealer where they informed the contact that the tires were balanced and needed to be rotated. The vehicle was repaired however, a month later the failure persisted. The vehicle was taken back to the dealer where it was diagnosed that the rear tires needed to be replaced. The vehicle was repaired but a few months later the failure recurred. The vehicle was taken back to the dealer where it was diagnosed that the front tires were worn unevenly and a four-wheel alignment was needed. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 450.