2018 Mercedes-Benz GLC 300 Problems
Owner-reported complaints filed with NHTSA, grouped by component
Data refreshed
What this page shows
Everything below is an owner-reported complaint submitted to NHTSA about the 2018 Mercedes-Benz GLC 300, grouped by the component NHTSA recorded on the report. These are not confirmed defects, and they are not recalls. NHTSA does not verify most reports before publishing them, and a category with more reports in it is not evidence that a part is defective.
Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.
Reports by component
Ranked by how many owner reports name each component category
- Engine2827.2%
- Electrical1312.6%
- Body & structure98.7%
- Driver assistance98.7%
- Seat belts87.8%
- Fuel system76.8%
- Powertrain (other)76.8%
- Airbags65.8%
- Brakes54.9%
- Visibility32.9%
- Steering32.9%
- Exterior lighting11.0%
- Interior & seats11.0%
- Suspension11.0%
- Transmission11.0%
- Other / unspecified11.0%
Percentages are of component mentions. A single complaint can name more than one component, so these do not sum to the total complaint count.
Each component in detail
What the reports in each category say, in the owners' own words
Engine
Reports naming the engine itself — including stalling, misfires, oil consumption, cooling and internal engine components.
From owner reports, verbatim
Error code P052E71 on a 2018 Mercedes-Benz GLC 300 4MATIC means the Positive Crankcase Ventilation (PCV) Regulator Valve Performance has a malfunction, specifically that the partial-load ventilation valve actuator is blocked. By research, i found that this is a very common problem on those engines, and no recalls from the company to fix their fault.
Component Failure: The vehicle is equipped with the M274 2.0L turbocharged engine, which suffered a major internal mechanical defect. An authorized Mercedes-Benz dealership diagnosed the vehicle at 79,504 miles with a malfunction in the crankcase ventilation system alongside severe internal defects, quoting a total repair estimate of $9,851 to perform extensive engine work. Safety Risk: This known manufacturing defect involves premature failure and cracking of the pistons, which poses an immediate safety hazard due to potential catastrophic engine failure and sudden, complete loss of motor power while driving at highway speeds. The manufacturer has failed to offer an extended warranty or recall for this known issue on the 2018 model year.
Electrical
Reports naming the electrical system — wiring, battery, charging, control modules, infotainment and electrical accessories.
From owner reports, verbatim
Safety Issue: Infotainment display screen produces scrambled pixels during Apple CarPlay navigation while driving. Description: When Apple CarPlay is connected and navigation is in use, the vehicle's infotainment display screen suddenly produces scrambled pixels, rendering the map and display unreadable. This malfunction occurs without warning while the vehicle is in motion, creating a dangerous visual distraction for the driver and uncertainty of where and when to turn or exit. This is a known, recurring issue. On January 7, 2021, I brought this problem to Mercedes-Benz of Indianapolis (Repair Order #624027), where a firmware update was applied and the issue was allegedly resolved. The fix has not proven permanent — the problem has since recurred and continues to present a safety hazard while driving. Despite this being a widely documented issue affecting numerous Mercedes owners, Mercedes-Benz has not issued a recall or technical service bulletin that I am aware of. My dealer is requiring a diagnostic fee of over $250 to inspect the vehicle, and Mercedes-Benz USA customer service has been unreachable. Requested Action: I am requesting that NHTSA investigate this issue and consider whether a Technical Service Bulletin or recall is warranted given the safety implications of a sudden display malfunction while driving.
I had the engine light come on and took it to the dealership. They quoted me over 8 thousand dollars to fix. I took it to a repair shop that works on luxury cars and they fixed it for less than 1000 dollars. I had to have the transducer fixed in the turbo in my engine and when they did that they found oil in the electrical harness. That was caused by the oil seperator. They told me that it was a manufacture defect that has been well documented and to take it back to Mercedees Benz. They looked and found the oil but said my car did not produce a code and could not fix it. We escalated it to corporate that reviewed my case and said they still would not fix until it produced a code. Mercedees implemented an extended warranty for my car back in 2022 for emissions. They said they would cover it if it produces a code. I researched this problem and it said it posses a risk to me, my passengers and the public if it quits running or causes a fire. Corporate said its not a problem yet.
Body & structure
Reports naming the vehicle structure, frame, body panels, doors, hood and trim.
From owner reports, verbatim
While driving on interstate 4 in Florida with our grandchildren going approximately 70 mph the sunroof on our 2018 Mercedes GLC just exploded no object came into the vehicle and while glass came into the vehiclenot all the glass that made up the sunroof came into vehicle suggesting a pressure issue as apparently blew out
What component or system failed or malfunctioned, and is it available for inspection upon request? 2018 Mercedes-Benz GLC 300 Panoramic stationary sunroof between the windshield and sunroof glass panel disbonded while vehicle was in operation and almost caused an accident on the highway. How was your safety or the safety of others put at risk? Exterior panel disbonded while in operation and almost hit vehicles behind and could have caused an accident. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes diagnosis from the dealership that panel was coming loose. Then upon picking up my vehicle, panel disbonded on the highway. Dealer is Mercedes-Benz of Atlanta South. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? No inspection only completed by local Dealership. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? Excessive wind noise inside the cabin during vehicle operation. In addition, my year, make and model vehicle has already had a recall regarding this issue, however, Mercedes did not identify my vehicle VIN number for this recall and is refusing to repair this safety issue. But the exact issue occurred on my vehicle. The NHTSA campaign numbers for the two recalls are 17V715000 (MBUSA number 2017110009) and a revised campaign in 2021 21V197 (MBUSA number 2021070010), which states “Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2017-2018 GLC300, GLC300 4Matic, and GLC43 AMG vehicles. The fixed panoramic sunroof frontal and side plastic panels may have insufficient bonding, allowing the panels to separate during vehicle operation”. Warning signs for these recalls are “high wind noise inside the cabin” which is EXACTLY what was diagnosed on my vehicle by the dealership. Please contact Mercedes-Benz and require them to re-assess the VIN numbers identified with the recalls.
Driver assistance
Reports naming forward-collision avoidance, lane keeping, back-over prevention, cruise control and related electronic driver-assistance systems.
From owner reports, verbatim
While pulling into a parking spot with my foot hovering above/on the break, the car lurched forward as if someone had floored the gas pedal. As my foot was already on the break, I slammed down onto the break and the car came to a stop, several feet ahead of the top of the parking spot, and into the woods. I called roadside assistance for the vehicle to be towed to the dealership for repair, as I did not find it safe to drive it. The dealership was unable to replicate the issue, but they told me that due to the severity of the issue, they weren't supposed to check it themselves. Instead, I needed to report a case to Mercedes Corporate and the communication from here would be handled directly between corporate and myself. It's been over three weeks since this occurred, and I have not received communication that the car has been tested further, or any next steps. The car is at the dealership. It's also important to note that this same issue also happened months before, while backing out of a parking spot in reverse. I didn't report it because it was a confusing thing to happen and I couldn't believe a car would gas on it's own. When it happened a second time, I knew it was a problem. This was not a case of user error or the floor mat being in a wrong position. What component or system failed or malfunctioned, and is it available for inspection upon request? Speed control / yes How was your safety or the safety of others put at risk? The car spontaneously accelerated and could have caused harm if people or structures were in its path. Has the problem been reproduced or confirmed by a dealer or independent service center? Has not been reproduced Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Not that I know of Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? No
The car does not go into drive from reverse and will sometime automatically shift itself from a low drive gear (D1) into Neutral without warning. After this happens - the car also can't get back into D1. It takes about 20 seconds for the car to shift back into a Drive gear and it will jolt into D3 violently. This has been a scary experience on many occassions - especially at red lights when this happens and we can't get the car out of neutral for some time. This was diagnosed by mercedes dealership near us as a fawlty sensor in the transmission. It is extremely expensive to fix and is specific to mercedes meaning it has to be done by a MB dealership. We applied for good will for assistance but were denied. The car has been maintained very well - this is not a maintenance issue but a specific sensor failure of a mercedes sensor in the transmission. We are thankful no one was hurt - we had our 8 year old daughter in the car when stalling out several times at red lights and it's been a very scary situation.
Seat belts
Reports naming seat belts, buckles, retractors and pretensioners.
From owner reports, verbatim
The contact owns a 2018 Mercedes-Benz GLC300. The contact stated that when the driver's side seat belt was buckled, the seat belt alarm chimed as if the seat belt was not buckled. The contact had to buckle and unbuckle the seat belt several times before the warning chime stopped. The contact had taken the vehicle to a local dealer who diagnosed the vehicle and determined that there was no issue with the seat belt system. The vehicle was not repaired. The contact stated that the failure was intermittent. The contact researched online and related the failure to NHTSA Campaign Number: 19V788000 (Seat Belts) however, the model year was not included. The manufacturer was informed of the failure. The failure mileage was approximately 48,000.
Rear seat belt latch plates (both driver and passenger side) retracted into the rear side paneling behind the seat. Both seat belts are now unusable. Issue occurred after rear seats were folded flat and then returned to upright position. Vehicle does not have dynamic locking tongue latch plates in the rear seats. MB dealership and MB customer care both claim that vehicle is not under NHTSA recall 18V-177 despite fitting the issue description, make & model, and production date.
Fuel system
Reports naming fuel storage or delivery — tanks, pumps, lines, injectors and fuel leaks.
From owner reports, verbatim
Check engine light with code P052E.
Car failed to accelerate due to faulty fuel pump, fuel tank, etc. Car stopped and died several times in the middle of heavy traffic. Mercedes Benz of West Houston, Sewell Dealership, has my car that was towed to them late afternoon on 3/5/2024. I have owned a Mercedes for over 40 years and never had this occur or be scared due to the car’s lack of performance.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Powertrain (other)
Powertrain reports that are not specifically the engine or transmission — driveshafts, axles, transfer cases and differentials.
From owner reports, verbatim
Component Failure: The vehicle is equipped with the M274 2.0L turbocharged engine, which suffered a major internal mechanical defect. An authorized Mercedes-Benz dealership diagnosed the vehicle at 79,504 miles with a malfunction in the crankcase ventilation system alongside severe internal defects, quoting a total repair estimate of $9,851 to perform extensive engine work. Safety Risk: This known manufacturing defect involves premature failure and cracking of the pistons, which poses an immediate safety hazard due to potential catastrophic engine failure and sudden, complete loss of motor power while driving at highway speeds. The manufacturer has failed to offer an extended warranty or recall for this known issue on the 2018 model year.
The contact owns a 2018 Mercedes-Benz GLC300. The contact stated that while driving at various speeds, the vehicle shifted into gear initially without warning. The contact stated that while stopped at a light, the vehicle shut off with the "Transmission Malfunction Stop" message displayed on the instrument panel. The contact was unable to move the vehicle, and the vehicle was towed to an independent mechanic. The mechanic ran a diagnostic test on the vehicle and initially stated that the front drive wheel sensor was defective; however, the contact was then informed that there were no issues with the sensor. Neither the dealer nor the manufacturer was notified of the failure. The vehicle was not repaired. The failure mileage was approximately 90,000.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Airbags
Reports naming the air-bag system — deployment behaviour, inflators, sensors and warning lights.
From owner reports, verbatim
The contact owns a 2018 Mercedes-Benz GLC300. The contact stated that while operating the vehicle, the message "Front Air Bag Malfunction" was displayed, and the horn became inoperable. The vehicle was taken to the local dealer who diagnosed that the steering column and air bag clock spring were faulty and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure and informed the contact that the VIN was not included in NHTSA Campaign Number: 17V627000 (AIR BAGS). The contact stated that the vehicle had experienced the failure listed in the recall. The failure mileage was 60,000.
I was backing out of my driveway and was putting the car in Drive when the airbag located in my steering wheel deployed without a reason. The car has not been inspected by anyone as of today. I was told there was a warning but that it was not of immediate attention in November of 2024.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Brakes
Reports naming service brakes, the antilock braking system, brake hoses, master cylinders or the parking brake.
From owner reports, verbatim
WHEN I WAS PULLING INTO A PARKING SPOT AT A LOW SPEED, THE CAR ACCELERATED AND LURCHED FORWARD, HITTING A WALL, WHICH DEPLOYED THE AIRBAGS. WHEN THE CAR STARTED TO ACCELERATE, I HIT THE BRAKES BUT THEY DID NOT ENGAGE.
WHEN BRAKING, THE BRAKES MAKE A GRINDING NOISE. THIS HAPPENS ANY TIME YOU APPLY THE BRAKES WHEN I AM BACKING OUT OF THE GARAGE OF MY HOME AND WHEN I STOP AT STOP SIGNS AND STOP LIGHTS AND WHEN TRAFFIC IS AT A STAND STILL ON THE MAIN THOROUGHFARE. THE NOISE WILL EVENTUALLY CEASE DEPENDING ON HOW OFTEN THE BRAKES ARE APPLIED. THIS IS AN ONGOING ISSUE THAT STARTED IN AUGUST, 2018 AND CONTINUES AS OF FEBRUARY 10, 2019.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Visibility
Reports naming windshields, glass, wipers, defrosters and mirrors.
From owner reports, verbatim
The windshield washer pump failed due to the Sam unit. Failing I was in the mountains, started my car the windshield wiper malfunction light came on the wipers worked for a minute, so I turned them off, drove over the pass and tried to use my wipers, and they did not work. The back wipers did work. I took my car to my mechanic in Cheyenne, who discovered that’s the SAM unit Ruined the windshield washer pump. No one else has inspected it other than my mechanic. I have learned that there are others complaining of the same issue online. This is a dangerous issue when you are driving in a storm with no windshield wipers. My mechanic believes this should be a recall issue, and so do I. The Mercedes dealership said my mechanic, a faulty Sam unit to replace the Sam unit that went out. Now my car is throwing all kinds of codes and the back windshield wipers do not work.
The contact owns a 2018 Mercedes-Benz GLC300. The contact stated while driving 60 MPH, the exterior panel between the windshield and sunroof detached, creating a hazardous road debris. The vehicle was taken to the dealer, who diagnosed a failure with the exterior panel adhesive bonding agent. The vehicle was not repaired. After investigating the failure, the contact related it to NHTSA Campaign Number: 21V197000 (Structure) and 17V715000 (Visibility), but the VIN was not included. The manufacturer was notified of the failure, and a case was opened. The failure mileage was 51,000.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Steering
Reports naming the steering system — racks, columns, power-steering assist and steering linkage.
From owner reports, verbatim
The contact owns a 2018 Mercedes Benz GLC 300. The contact stated while attempting to park, a loud clanking noise was coming from the steering wheel as the air bag warning light illuminated. The vehicle was taken to the dealer where it was diagnosed that the clock spring in the steering wheel which caused the steering wheel to fail and the steering module needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and referred the contact to the NHSTA Hotline for assistance. The approximate failure mileage was 62,700
The contact owns a 2018 Mercedes-Benz GLC300. The contact stated that while driving at various speeds, the steering wheel malfunctioned, and became difficult to turn in either direction. The vehicle was taken to the local dealer who diagnosed that the electronic power steering module was faulty and needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure, but no assistance was offered. The approximate failure mileage was 70,000.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Exterior lighting
Reports naming headlights, tail lights, turn signals and other exterior lighting.
From owner reports, verbatim
ELECTRONIC SHIFTIER ISSUE. CAR WILL NOT DO WHAT IS BEING INPUT TO THE SHIFTIER. PARTICULAR ISSUE WHEN GOING FROM PARK TO DRIVE, DRIVE TO REVERSE, OR PARK TO DRIVER OR REVERSE. (NOTE THAT THE PRESSURE ON BRAKE PEDAL HAS ALWAYS SEEMED EXCESSIVE TO ME. HAVE HAD ISSUE WHERE CAR GOES INTO NEUTRAL WHEN TRYING TO PLACE THE SHIFTIER INTO PARK. I HAVE HAD TIMES WHERE CLEARLY THE VEHICLE DOESN'T REGISTER THAT THE BRAKE IS ACTUATED WHEN IT IS. HAVE HAD INSTANCE WHERE VEHICLE STARTS OFF IN DRIVE AND ROLLS UNDER POWER AS IT DIDN'T SHIFT INTO PARK AS INSTRUCTED. HAVE ALSO ENCOUNTERED THE CAR WALKING A STOP LIGHT. WHERE THE CAR CREEPS BECAUSE THE INTENDED BRAKE PRESSURE TO MAINTAIN A COMPLETE STOP ISN'T SUFFICIENT. SECOND SAFETY CONCERN, VEHICLE HAS HEADLIGHTS IN AUTO(NIGHT TIME OR LOW LIGHT) OR ON AND HEADLIGHTS & TAILLIGHTS ACTIVE. COME TO A STOP WITH STOP/GO ECO ON, ENGINE TURNS OFF AS IT SHOULD. HOWEVER ON RESTART HEADLIGHTS & TAILLIGHTS/BRAKE LIGHTS DIM. REAPPLY BRAKES, VEHICLE TO COMPLETE STOP. STOP/GO TURNS ENGINE OFF, FOOT OFF BRAKE ENGINE TURNS BACK ON, BEHAVIOR REPEATS. NOTE THAT LED DLRS DO NOT EXHIBIT DIM WITH HEADLIGHTS. (MERCEDES HAS NO PLANS ON DOING ANYTHING TO CORRECT DESIGN FLAW)
Too few reports in this category for a page of its own — they appear in the full complaint list.
Interior & seats
Reports naming seats, latches, locks, linkages and interior fittings.
From owner reports, verbatim
TL* THE CONTACT OWNS A 2018 MERCEDES-BENZ GLC300. THE CONTACT STATED THAT THE VEHICLE DOORS AUTOMATICALLY LOCKED WITH THE KEYS INSIDE OR OUTSIDE OF THE VEHICLE. THE VEHICLE WAS TAKEN TO MERCEDES-BENZ OF ALEXANDRIA (200 S PICKETT ST, ALEXANDRIA, VA 22304, (703) 341-2100) FOR DIAGNOSTIC TESTING AND REPAIRS. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE VIA EMAIL. THE FAILURE MILEAGE WAS 6,124. THE VIN WAS NOT AVAILABLE.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Suspension
Reports naming suspension components — springs, struts, shocks, control arms and related hardware.
From owner reports, verbatim
when the car is in drive it will stop like it is in park unable to drive or put in reverse. This happens at random times on the road. The car will then skip gears and go into Neutral then skip an again on its own and go into drive.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Transmission
Reports naming the automatic or manual transmission, including shifting behaviour, shudder, slipping and transmission control modules.
From owner reports, verbatim
The contact's friend owns a 2018 Mercedes-Benz GLC 300. The contact stated that while the owner was driving at an undisclosed speed, the accelerator pedal was depressed, but the vehicle failed to accelerate as intended, and the gear shifter independently shifted to neutral(N). No warning lights were illuminated. In addition, the contact stated that the failure was persistent. The contact stated that the owner forced the gear shifter out of neutral(N). The vehicle was taken to the dealer, where it was diagnosed that the transmission control unit had failed and needed to be replaced. The vehicle was not repaired. The contact related the failure to an unknown recall, but the VIN was not included in a recall. The manufacturer was made aware of the failure, and a case was filed. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was unknown.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Other / unspecified
Reports whose component NHTSA recorded as unknown, or that do not map to one of the categories above.
From owner reports, verbatim
TL* THE CONTACT OWNED A 2018 MERCEDES-BENZ GLC300. WHILE DRIVING 55 MPH, THE REAR DRIVER'S SIDE TIRE WAS PUNCTURED. THE CONTACT STATED THAT THE VEHICLE WAS EQUIPPED WITH 18 INCH RUN FLAT TIRES. THE CONTACT PULLED THE VEHICLE OVER TO THE SIDE OF THE ROAD. AFTER WAITING APPROXIMATELY 70 MINUTES ON THE SIDE OF THE ROAD, THE TIRE BURST INTO FLAMES. THE CONTACT WAS UNABLE TO PROVIDE THE TIRE MANUFACTURER, TIRE LINE, COMPLETE TIRE SIZE, OR DOT NUMBER. THE CONTACT STATED THAT THE FIRE ORIGINATED IN THE WHEEL WELL OF THE VEHICLE AND WAS NOT NECESSARILY CAUSED BY THE TIRE PUNCTURE. THE FIRE DEPARTMENT WAS CONTACTED AND WAS ABLE TO EXTINGUISH THE FIRE. A FIRE REPORT AND A POLICE REPORT WERE FILED. THE VEHICLE WAS DESTROYED AND TOWED FROM THE SCENE. THERE WERE NO INJURIES SUSTAINED. THE DEALER AND THE MANUFACTURER WERE NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 1,110.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.
Elsewhere on this vehicle
Data sources
- NHTSA Office of Defects Investigation — owner-reported complaints and the components recorded on them
Data on this page last refreshed .