2020 Mercedes Benz GLC300 Problems and Top Complaints – Is Your Car A Lemon?

Powertrain, wheels, and vehicle speed control issues among the top complaints received by the NHTSA from vehicle owners

Updated on Author: Brian Jones

Updated on Author: Brian Jones

When a driver wants a top-notch vehicle, they look toward the Mercedes lineup. The 2020 Mercedes Benz GLC300 has a lot to offer, considering the automaker has often claimed owners want “the best or nothing.” However, this particular model seems to miss the mark with a defective powertrain, faulty tires and a dangerous vehicle speed control system.

Click on other model years to view more problems: 2021   2022

Don’t be stuck with a lemon. You have legal rights to cash, return or buyback.

The law makes Mercedes-Benz pay legal fees.

We've fixed thousands of lemon problems. Message or call 877-795-3666 today.

NHTSA Complaints for the 2020 Mercedes Benz GLC300

Complaint CategoryNumber of Complaints
Unknown Or Other
Back Over Prevention
Electrical System
Forward Collision Avoidance: Automatic Emergency Braking
Vehicle Speed Control
Air Bags
Power Train

Problems with the Powertrain

The most important part of any powertrain is the transmission, but the entire system must run smoothly to enjoy the open road. Yet, owners of the GLC300 have nothing but complaints to express.

Here is one from the Edmunds site. “My vehicle has 8800 miles on it. Check engine light came on at 8500 miles and I made it to a dealer, where they diagnosed a faulty transmission control unit. Since it’s not in stock, I’ll have to call ahead to another dealer to get it fixed. When they did the A service (early), they overfilled the oil, so now the car smokes like a chimney but I was told it will burn off. I thought a new Benz would be great for a cross country road trip. Instead I’m discovering that the GLC was a bad purchase decision. If you’re reading this, know that we’ve owned 9 Mercedes over the last few decades. And this will be the last.”

To be “the best,” Mercedes has to ignore the problems of consumers. That’s why the only published service bulletins have to do with minor electrical system complaints that won’t hinder the drivability of the vehicle. There’s nothing said about the powertrain or the defective parts. Drivers are being kept in the dark and are starting to wonder if “nothing” would have actually been the better option.

Problems with the Wheels

With a faulty transmission, the ride is rough, but installing the wrong tires can have the same disastrous consequences. 

Here’s one example left with Edmunds. “Why drive an SUV if the tires can’t handle graded dirt roads? The Pirelli no-flat tires puncture very easily. This is my last GLC.”

Again, there’s nothing to find in the Service Bulletins from Mercedes about this matter. Instead, the company hopes that owners take their GLC out on the road and don’t notice the intense problems keeping it under control. It operates like an SUV with a mind of its own, which isn’t what most people consider “the best.”

Problems with the Vehicle Speed Control

Modern vehicle speed control systems are designed to make the ride safer and more enjoyable. But what happens when these systems malfunction?

Here’s an illustration from an Edmunds user. “For 45 years I have been a loyal Mercedes-Benz owner – mostly E Class vehicles with the exception of my 2017 and 2020 GLCs. The 2020 has a severe safety issue which may cause injury or death. When the cruise Control is set it automatically changes the set speed as the road speed limit changes. A wonderful feature however, the GLC senses the exit ramp speed limit as I travel the highway and changes the cruise Control to the exit ramp speed limit. So, traveling at a speed set to 70 mph on the interstate, I pass by an exit and the cruise Control changes to 30 mph and applies the brakes. Vehicles behind me screech their tires, blow their horns and make unmentionable comments and gestures as they pass.”

Again, Mercedes has remained silent. At this point, it might be better if the luxury automaker changed its tagline to – the best or we won’t tell you otherwise.

Your Lemon Law Legal Rights

Think you have a lemon? Sit back and let the experts work out your lemon case at no cost to you. The law makes Mercedes-Benz pay legal fees. You may be able to get your lemon out of your life. Every year, auto manufacturers buy back, replace or pay cash settlements to thousands of ‘lemon’ owners like you.

Complaint Data

CategoryBack Over Prevention
DateMar 20, 2023
The contact owns a 2020 mercedes-benz glc300. The contact stated that the rearview camera displayed a reverse mirror image. The contact related the failure to nhtsa campaign number: 22v232000 (back over prevention). The vehicle was not diagnosed nor repaired by an independent mechanic or dealer. The manufacturer was made aware of the failure. The failure mileage was approximately 60,000.
CategoryUnknown Or Other
DateJan 09, 2023
The manufacturer service dealer (mercedes) has been unable to clear a vin recall notice, even though they say it has been updated. The system still says it's recall. They have had the vehicle for almost 30 days, and have not been able to fix the issue. The recall is for a software update, and the dealer says they've done everything at mercedes of ft lauderdale, and the manufacturer, (mercedes) says it's the dealer problem. The dealer says its mercedes problem, and we as the customer are stuck in the middle and have no car
CategoryBack Over Prevention, Electrical System
DateOct 27, 2022
The contact owns a 2020 mercedes-benz glc300. The contact received notification of nhtsa campaign number: 21v354000 (back over prevention, electrical system) however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure. Parts distribution disconnect.
CategoryFuel/propulsion System
DateOct 01, 2022
Driving slowly through a parking lot and had to stop for pedestrians. When the path was clear, the car would not accelerate. It only idled forward and slowly reached about 5 mph. Stepping on the accelerator pedal gave no response after repeatedly trying to accelerate. No warning lights came on to alert me of a problem. I was able to pull into a parking spot and after shutting off the ignition and turning back on, the throttle responded as normal. This was a very scary situation but at least it happened in a parking lot.
CategoryBack Over Prevention: Rearview System Braking
DateJul 22, 2022
In july 2021, mercedes notified me of nhtsa recall #21v354 n certain my 2019-2021 mercedes-benz vehicles listed above, under certain conditions, the mbux multimedia system might not start and the display might remain black, or could reboot unintentionally after 50 seconds of initial startup. Accordingly, the rearview camera image might not be displayed or the display might be interrupted which could reduce the driver's rear view, and increase the risk of a crash or injury. Mercedes indicated the update would be pushed to the car over the air (ota). More than a year later, the update still has not been pushed ota. I took the car to the mercedes dealer that I bought the car from and they were unable to install the update either. It's apparent that mercedes ota process does not work for all vehicles, and mercedes has provided me no method by which I can get the update completed.
CategoryForward Collision Avoidance: Automatic Emergency Braking, Lane Departure: Assist, Lane Departure: Warning
DateMay 20, 2022
Self driving assist, adaptive cruise , emergency braking assist do not work. Taken to dealer three times , unable to correct. Returned to customer with out paperwork documenting repair of safety systems. Problems are still in I repaired state. Emergency braking system warning message has activated 15-20 times after receiving car back. Other existing problems are still on going as well. Requested district service manager consult the situation and advise. Love car , want to have repaired . Looking to add additional glc to household . Hope repair is possible . ????! Hate to have accident, bad for health. Please contact. [xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).
CategoryPower Train
DateApr 24, 2022
It took a few minutes to be able to completely turn left out of a shopping center while waiting in line. When finally able to turn left, the car stalled into what appeared to be neutral where I had no control to increase speed and was turning very slowly. Oncoming traffic from both ways were coming and luckily stopped on-time. I had to turn off the entire car and restart in the middle of the road in order to be able to drive again. There could've been a massive collision if cars were not paying attention on both sides. Note that the car was not in neutral at the time and was in drive the entire time. This same incident also happened over a year ago but thought it was something I could've done wrong or was a one-time thing. Now that it's happened twice confirms that there is something wrong with the car. The car did not indicate a power failure or warning lights during this incident. I have an appointment with mercedes on 4/25 to get this looked at. This has been reported on other models from other car owners but we have never seen a recall. This is a serious malfunction and could've gotten myself or others killed. I do not feel safe driving this car unless it is fixed.
CategoryElectrical System:ignition, Engine
DateMar 04, 2022
The contact's wife owns a 2020 mercedes-benz glc300. The contact stated that while his wife was driving at an undisclosed speed, the vehicle stalled. The vehicle was towed to the dealer and diagnosed with ignition failure. The contact was informed that the engine needed to be replaced. The vehicle was not repaired and remained at the dealer. The manufacturer was made aware of the failure but declined to buy back the vehicle and offered a two-year service plan for a free oil change per year. The failure mileage was approximately 30,000.
CategoryBack Over Prevention, Electrical System
DateFeb 25, 2022
The contact owns a 2020 mercedes-benz glc300. The contact received notification of nhtsa campaign number: 21v354000 (back over prevention, electrical system). The dealer was notified of the recall and informed the contact that the recall repair would be performed over-the-air (ota). The contact then called the manufacturer and was informed that the update was not available; he was informed that there was a waiting list and that he would receive a notification when the update for the vehicle was available. The contact had not experienced a failure. Parts distribution disconnect.
DateJan 13, 2022
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.
CategoryUnknown Or Other
DateSep 30, 2021
I have received recall notice 3 months ago for software update. The update was supposed to happen over the air which it didn't. I need this update to finish asap because I need a recall clearance letter. This update took way too longer than it should have. Please solve this issue for me. Regards,
CategoryUnknown Or Other
DateAug 19, 2021
Manufacturer recall number2021060021 nhtsa recall number21v354 mercedes dealership said they're unable to complete this recall, and it must be done via ota update. Vehicle has no ota update available, mercedes refused to push update when requested, and could provide no information on when an ota update would be available.
CategoryAir Bags
DateMay 28, 2021
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.
DateApr 29, 2021
The sunroof of our car shattered by itself when we were driving on a city street. There was no projectile that caused the sunroof to shatter and the dealership was able to confirm that. But the dealership and the company are unable to say for certain why this happened and whether or not this will happen again. The incident caused glass to fall on all our passengers and the sound of the glass shattering during driving really scared us. We are concerned for our safety and even more concerned that mercedes is unable to diagnose why this happened and are not able to say for sure that it would not happen again.
CategoryUnknown Or Other, Vehicle Speed Control
DateApr 26, 2021
I was driving and stopped car to make a turn waiting for incoming traffic to clear. When I went to accelerate after traffic cleared, the car would not go above 0. 5 miles per hour. I made sure the gear had not shifted to neutral, it was on comfort drive. I changed to sports drive and the car still would not accelerate above 0. 5 miles. I was now stuck in the middle of intersection with incoming traffic, so I tried to reverse. The car reversed no faster than 0. 5 miles per hour. I turned car off and back on, and acceleration then worked. Very scary. I was lucky incoming traffic avoided me. Big safety hazard. Dealership so far has not been able to replicate the issue, but I read other blogs where people experienced a similar event.
CategoryUnknown Or Other
DateApr 06, 2021
Received safety recall from mercedes benz (nhtsa recall #21v058) and have tried to schedule with dealer on several opportunities to get the repairs completed and they continue stating they cannot perform the recall repairs
CategoryForward Collision Avoidance: Automatic Emergency Braking
DateMar 29, 2021
While driving under an overpass the breaks activated abruptly and unexpectedly. We where going about 35 miles per hour and if it wasn't for the seat belts we would of hit the windshield. Luckily no one was following us up close.. It happened twice at the same spot where there is a shadow from the overpass (at same time of day)
CategoryUnknown Or Other
DateMar 18, 2021
Received a safety recall notice to have corrective action taken to the communication module to communicate the correct vehicle's location for the emergency call system; however, local dealer says they cannot resolve. Copy of recall notice attached - see below.
CategoryUnknown Or Other
DateDec 31, 2020
The audible tic-tok sound of the turn signal is way too soft. The sound is supposed to give one notice that the turn signal is on. It simply isn't loud enough to provide that feedback. Consequently I often find that I'm driving down the street having completed a half-turn ( one where it doesn't trigger a shut off) with my turn signal on for blocks before I notice that the turn blinker is still on.
DateFeb 26, 2020
The vehicle wonders within the lane when mercedes distronic driver assistance is activated, particularly on gentle curves at highway speeds. It will hit lane bumps unless the driver actively steers away from the lane markings. The 2020 glc3004matic has been doing this since we purchased it new on january 2, 2020. Mercedes dealer has checked the vehicle and is now describing the vehicles behavior as normal. According to mercedes this is a new driver assistance package in the 2020 glc. It is a major safety hazard if the vehicle is not actively controlled by the driver at all times. This is not an assistance package as described by mercedes. We have driven older mercedes with the distronic system that stayed in the lane vs. The wondering. We do not take our hands off the steering wheel the vehicle does this on it's own prior to any warnings related to driver awareness or actions. This action by the vehicle when distronic is activated will cause serious life threatening accidents.
CategoryService Brakes
DateJan 15, 2020
Driving along random traffic no pattern, automatic brake assist is temporarily not active , bright yellow wording, danger auto brake assist will not function at this time.

Who are we? We are Lemberg Law, a Consumer Law Firm

Lemberg Law is a consumer law firm helping victims of bad manufacturing and run-arounds from auto companies. We are ranked A+ by the BBB. Call our Helpline today!  There is no charge unless we win.


Share your story

Does this ring a bell? Have you had a bad experience too? Sound off and share your experience with other visitors in the comment box below.

Brian Jones

About the Author:

Brian Jones spent more than 20 years working as an ASE Certified Master Tech and Parts Specialist at multiple dealerships. Brian has become an authority in the industry, traveling across the country to consult for car dealerships and contributing his expertise as a writer for several major automotive publications. In his spare time, Brian enjoys working on pickup trucks, muscle cars, Jeeps and anything related to motorsports.

See more posts from Brian Jones
  • MrsLady

    Alan & Sheri I’m having an issue with my 2021 and being treated the same way before I’m even able to see what my options are after getting this devastating news of a mechanical engine failure. Lemon law needs to change the mileage criteria, 24k isn’t long enough to determine if it’s a lemon.

  • Alan W

    I purchased a GLC 300, 2020, that now has a manufacturing defect in the casing around the piston. It has been a nightmare dealing with w dealership. I submitted a claim to Mercedes’ Corporate and the dealership became anger at me stating it my fault, they requested that I return the loner car because I have the claim on buy back.?I have no other vehicle. I had to rent a car $60.00 a day and still responsible for paying the car note. I thought I was buying a dependable SUV. My whole perception and image of Mercedes Benz has changed. I would never purchase another Mercedes’s.

  • Virginia S

    I bought a Mercedes GLC 300 on March 18, 2022 It has a major problem with the steering module. I have had it in the shop 2 times now and still has not been fixed. As I understand it Mercedes has to provide an update to the module so the service department can upload it to my car. To do that they have to keep my car while they install the software. My car is not the only one with this same problem. There is a waiting list with all lot of cars like mine. I have been buying Mercedes-Benz since 1970! I have never had a problem like this with any of my cars.

  • Sheri S

    I have a 2016 Mercedes GLC with 33, 000 miles
    The warranty expired last year. I have complied with all services.
    I’ve replaced tires, both batteries, brakes etc which seemed excessive considering low mileage
    Today I found out I have a cracked piston and the engine needs to be replaced at approximately $13,000!
    Again my car has 33,000 miles ! This should not be happening !

Leave a Reply or Comment

Write a comment below to share online. Or, instead you can to our legal team.

Please select your star rating.

Briefly describe your experience Briefly describe your experience

What’s your name? What’s your name?

What’s your phone number? Please enter a valid phone number

Want to know if you could sue? Get a free legal evaluation Lemberg Law?

Get Your No-Obligation
Case Evaluation

Send a secure message to our legal team.

What’s your name? What’s your name?
What’s your email address? What’s your email address?
What’s your phone number? What’s your phone number?
Briefly describe the problem Briefly describe the problem
Confidentiality Guarantee: We keep your information completely confidential and will not send you spam or sell your information.