2021 Mercedes-Benz GLB 250 Problems

When my car sits in the rain for long periods of time, while driving, it will automatically switch into neutral and give me a "transmission malfunction stop" & "service required do not shift gears visit dealer" sign on the dash. This has happened at least 7 times in 2 years since March 2024. The latest time it happened was last week. I will get into my car after a day at work, when it has been raining, drive a few miles and the car will switch into neutral and display those signs. This is incredibly dangerous for my safety as the driver, any passengers and any other cars on the road. While going 55+ miles an hour, my car, without any warning shifts into neutral. I have taken it to my local dealership for inspection every time that it happens and they have repeatedly told me they cannot find a fix for it and do not know why it is happening besides a electrical problem due to water. They advised me to file a claim with corporate Mercedes but that was denied. I have photos and documentation from the dealership of when I have brought it in for inspection and they have confirmed the issue. They will not help with a solution for this problem. They have told me to pull over, turn the car on and back off to get it to go away but it continues to do the same repeated problem.

Engine locked up while driving out of state on the interstate. Vehicle lost all power and engine stopped functioning. Managed to pull over and stop the vehicle on the side of the interstate. Had truck towed to repair shop where they diagnosed connecting rod/crankshaft bearing failure, as well as lifter and cylinder misfire/failure on cylinder 7. Metal shavings were discovered in the oil, and engine locked up and cannot be repaired. I am currently in the process of having the engine replaced, but yes currently an inspection can still be performed, and I can provide statements and diagnostics from the mechanic. This failure put myself and my family in a scary situation. The engine was shaking violently before it stopped functioning and this made the truck very difficult to steer, not to mention this was during rush hour and we were in heavy traffic moving at speeds of 70mph+. Luckily we managed to get off the road, and to a safer location, but this left us stranded on the side of the road for 2 hours waiting on a tow. The vehicle was inspected by a GMC dealership initially where they only diagnosed lifter and cylinder misfire/failure. Due to the price of their quote to repair that issue, I took the vehicle to a certified mechanic, and thats when we found there was also connecting rod/crankshaft bearing failure prior to repairing the lifter/cylinder misfire. There were no prior warnings to this happening. No check engine lights, no noises, and no noticeable changes in the vehicle. Everything seemed to be operating normally.

The component that appears to have malfunctioned is the front axle integral carrier (front subframe) and the related front suspension geometry, as the vehicle now exhibits a persistent pull to the left and degraded steering stability after the dealer replaced the front lower control arms, engine mounts, and performed alignments; this area of the vehicle is fully available for inspection upon request. My safety and the safety of others were put at risk because the vehicle requires constant steering correction to avoid drifting left, creating a danger of unintended lane departure and loss of control, which aligns with the steering‑related risks described in NHTSA Recall 21V990 / MBUSA 2022070009, where failure of the integral carrier can impair steering and increase crash risk. The problem has been reproduced by me on every drive, though the dealer stated they “did not find anything,” despite alignment printouts showing front camber imbalance and lack of caster correction. The vehicle has been inspected twice by the authorized Mercedes‑Benz dealer, but they did not inspect or address the front axle integral carrier even though the recall documentation shows that corrosion or structural issues in this part can affect steering performance and connection to other components. There were no warning lamps or dashboard alerts; the symptoms began immediately after the dealer’s suspension and mount repairs, and the steering pull and unstable handling have continued ever since.

Escalating Safety Concern – Loud Clunking, Thumping, and Cracking from Front Axle at Low Speeds We are long-time loyal customers and currently own four identical Mercedes-Benz models. Unfortunately, one of our vehicles, a 2021 mb glb250 has recently developed severe clunking, thumping, and loud cracking noises originating from the front axle area, noticeable especially at low speeds. The problem appeared suddenly and is rapidly worsening. After researching the issue, we’ve discovered that many owners of the exact same model and model year report identical symptoms. This appears to be a widespread and recurring problem that raises serious safety concerns, particularly as it affects the front axle and is uncommon in other modern vehicles of this class and young age. Given the potential safety implications and the growing number of affected owners, we respectfully request that Mercedes-Benz investigate this issue promptly, acknowledge it as a known concern, and provide an appropriate inspection and repair at no cost to us. We love the brand and have always trusted its engineering and safety standards, which makes this experience especially distressing. We would greatly appreciate your immediate attention and a clear response on next steps.

Entire electrical system went out while driving causing check engine light to come on after the failure of system; there was no dashboard working at all when the system went out; without the dashboard out it was not certain if the vehicle was safe to drive anymore; the dealer has not been able to reproduce the problem; the vehicle has been with the dealer repair system for several weeks and have not been able to determine what happened; they have indicated that the vehicle had some type of water intrusion which short circuited the electrical system; the believes that the water entered into from the windshield area with a possible clogged water drain; there was no prior warning

The horn randomly starts honking while driving posing a serious safety risk. it makes driving the vehicle seem like it is stolen.

I purchased this vehicle in May 28 2025. I certified car. I took in for oil change Nov 17-2025. Found out they had lot of issues., left front bushing arm leaking. Rt engine mount leaking. Bad brakes battery low. Bad tire rt back passage side.front wheel axle and rear wheel axle is bad and screw on the engine mount is missing. Screw and leaking..?and the vehicle needed a alignment.

IT APPEARS AS IF THERE IS AN ISSUE WITH THE TRANSMISSION. IN THIS VEHICLE. WHEN YOU COME TO A STOP THE TRANSMISSION HAS A LOUD CLUNKING NOISE COMING FROM LEFT SIDE OF VEHICLE. THE CLUNKING OCCURS WHEN THE VEHICLE DOWNSHIFTS. IT CLUNKS FROM D4 TO D3, THEN D3 TO D2 , AND AGAIN AT D2 TO D1. I HAVE TAKEN IT TO THE DEALER NUMEROUS TIMES TO HAVE IT CHECKED. THE SERVICE MGR WENY FOR S TEST DRIVE WITH ME AND HEARD IT. I WAS THEN TOLD THE CLUNKING WAS " NORMAL" . I PURCHASED THE VEHICLE AS A CERTIFIED USED VEHICLE FROM THE SAME DEALER . THIS HAS BEEN OCCURING SINCE PURCHASE IN MAY 2024

I purchased this vehicle in May 28 2025. I certified car. I took in for oil change Nov 17-2025. Found out they had lot of issues., left front bushing arm leaking. Rt engine mount leaking. Bad brakes battery low. Bad tire rt back passage side.front wheel axle and rear wheel axle is bad and screw on the engine mount is missing. Screw and leaking..?and the vehicle needed a alignment.

This vehicle was purchased new, in cash, from the Mercedes-Benz dealership in Bellevue, WA. It was delivered to me, without being warned about the car being equipped with summer tires, the state of Washington has continuous rain, snow, and ice in a regular basis throughout the years, summer tires are not a good tire for an SUV such as this GLB unit in this region. On 12/27/2021 I went on an errand around my neighborhood, the road had snow and ice, and it had been serviced by our city's plows and deicer was present, during three occasions I had to stop for traffic lights, and my car skidded during all three occasions almost hitting another vehicle, and a pedestrian, my car was the only car skidding on the road, I am an excellent driver with not a single accident on my responsibility, and I have driven on snow and ice for years; this was not a novice's error. Furthermore, the car has a loud "clunk" noise coming from undercarriage, and sensations of tire slipping, possibly front and right corner, specifically when I perform a slow speed U-turn. This vehicle has not been damaged and has about 3,000.0 miles in the odometer, on 12/14/2021 I took it to the Mercedes-Benz dealership for inspection, they did not find any reason for the "clunk" noise and slipping of tires; this is when I was informed that my tires were summer tires and I needed to buy new all-weather, or winter tires, the tires "would not perform" in the winter, I was told by the M-B service representative. Here I am with a "high quality" new vehicle, with clunky scary noises, while sensing of tires slipping, and the dealership claims it to be "normal" and "safe", on top of that the car was equipped by factory with substandard tires for the region of final destination, all of which may cause accidents, damages, and/or injuries.

Driving on north bound of Merritt Parkway between exit 17 and 18. Today 12/10/25 9:28 AM My panoramic sunroof exploded ! all catch on video, driver on the vehicle behind me , came to check on me; and told me the glass went over four feet up in the air and then hit his vehicle windshield, I call Mercedes Benz customer service support to report the incident and open a case, they told me to drive to the closest dealer from the incident (Mercedes Benz of Fairfield) when I arrived and show the vehicle to the technician, he was trying to tell me that was my fault and he never heard such a thing of a sunroof explosion… and was looking for a reason to blame me, I told him I got all on video due to I have a dash camera that records the our side and the inside of the vehicle.. the outside temperature was 30 degrees Fahrenheit, and the inside temperature in the vehicle was set to 69 degrees… My speed was 55 to 56 miles per hour. Light to moderate traffic, the explosion sound like a gunshot, that was my first impression, some one shoot at me… The dealer, told me that I should call my insurance or Mercedes Benz and the only think they can do, is to tell me how much will cost to repair the damage.. and that they will park my car on a different building so don’t get rain on it, until I decided what I want to do.

The contact owns a 2021 Mercedes-Benz GLB250. The contact stated that the vehicle was parked in the garage; however, after driving out of the garage, the contact became aware of a crack on the windshield from the rear-view mirror ten inches downward. The contact stated that the crack seemed to be on the inside over the sensors. The vehicle had not yet been diagnosed or repaired. The dealer nor manufacturer was notified of the failure. The failure mileage was 13,716.

Entire electrical system went out while driving causing check engine light to come on after the failure of system; there was no dashboard working at all when the system went out; without the dashboard out it was not certain if the vehicle was safe to drive anymore; the dealer has not been able to reproduce the problem; the vehicle has been with the dealer repair system for several weeks and have not been able to determine what happened; they have indicated that the vehicle had some type of water intrusion which short circuited the electrical system; the believes that the water entered into from the windshield area with a possible clogged water drain; there was no prior warning

Detached wheel arch covers while driving

The contact owns a 2021 Mercedes-Benz GLB250. 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 contact stated that several unknown local dealers were contacted, and the contact was referred to the manufacturer for further assistance. The manufacturer was contacted, and a case was opened. The contact had not experienced a failure. Parts distribution disconnect. The contact stated that the manufacturer was able to complete the repairs necessary to fix the issue and no longer wishes to keep this complaint.

The contact owns a 2021 Mercedes-Benz GLB250. The contact received notification of NHTSA Campaign Number: 21V354000 (Back Over Prevention, Electrical System) however, the part to do the recall repair was not yet available. The local dealer was contacted. 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 and informed the contact that the part was not yet available. The contact had not experienced a failure. Parts distribution disconnect.

Engine locked up while driving out of state on the interstate. Vehicle lost all power and engine stopped functioning. Managed to pull over and stop the vehicle on the side of the interstate. Had truck towed to repair shop where they diagnosed connecting rod/crankshaft bearing failure, as well as lifter and cylinder misfire/failure on cylinder 7. Metal shavings were discovered in the oil, and engine locked up and cannot be repaired. I am currently in the process of having the engine replaced, but yes currently an inspection can still be performed, and I can provide statements and diagnostics from the mechanic. This failure put myself and my family in a scary situation. The engine was shaking violently before it stopped functioning and this made the truck very difficult to steer, not to mention this was during rush hour and we were in heavy traffic moving at speeds of 70mph+. Luckily we managed to get off the road, and to a safer location, but this left us stranded on the side of the road for 2 hours waiting on a tow. The vehicle was inspected by a GMC dealership initially where they only diagnosed lifter and cylinder misfire/failure. Due to the price of their quote to repair that issue, I took the vehicle to a certified mechanic, and thats when we found there was also connecting rod/crankshaft bearing failure prior to repairing the lifter/cylinder misfire. There were no prior warnings to this happening. No check engine lights, no noises, and no noticeable changes in the vehicle. Everything seemed to be operating normally.

In April 2025, my 2021 Mercedes-Benz GLB 250 (81,000 miles) suffered repeated engine issues caused by a cylinder head failure. The dealer attempted a cylinder head replacement, but during their own test drive after repairs, the engine completely seized and failed again on their property. This indicates a severe defect in the engine assembly that risks sudden power loss while driving, which could cause an accident. Prior to the failure, there were warning messages about misfires and rough idle. The problem has been confirmed by an authorized Mercedes-Benz dealer and the car has been kept at their shop since April, with no resolution. I am concerned this is a recurring safety defect affecting other GLB 250 vehicles. The vehicle is available for inspection and remains undriveable due to the failed engine. I request NHTSA to investigate for possible safety-related design or manufacturing defects that could cause sudden engine seizure and loss of power while driving.

The component that appears to have malfunctioned is the front axle integral carrier (front subframe) and the related front suspension geometry, as the vehicle now exhibits a persistent pull to the left and degraded steering stability after the dealer replaced the front lower control arms, engine mounts, and performed alignments; this area of the vehicle is fully available for inspection upon request. My safety and the safety of others were put at risk because the vehicle requires constant steering correction to avoid drifting left, creating a danger of unintended lane departure and loss of control, which aligns with the steering‑related risks described in NHTSA Recall 21V990 / MBUSA 2022070009, where failure of the integral carrier can impair steering and increase crash risk. The problem has been reproduced by me on every drive, though the dealer stated they “did not find anything,” despite alignment printouts showing front camber imbalance and lack of caster correction. The vehicle has been inspected twice by the authorized Mercedes‑Benz dealer, but they did not inspect or address the front axle integral carrier even though the recall documentation shows that corrosion or structural issues in this part can affect steering performance and connection to other components. There were no warning lamps or dashboard alerts; the symptoms began immediately after the dealer’s suspension and mount repairs, and the steering pull and unstable handling have continued ever since.

Escalating Safety Concern – Loud Clunking, Thumping, and Cracking from Front Axle at Low Speeds We are long-time loyal customers and currently own four identical Mercedes-Benz models. Unfortunately, one of our vehicles, a 2021 mb glb250 has recently developed severe clunking, thumping, and loud cracking noises originating from the front axle area, noticeable especially at low speeds. The problem appeared suddenly and is rapidly worsening. After researching the issue, we’ve discovered that many owners of the exact same model and model year report identical symptoms. This appears to be a widespread and recurring problem that raises serious safety concerns, particularly as it affects the front axle and is uncommon in other modern vehicles of this class and young age. Given the potential safety implications and the growing number of affected owners, we respectfully request that Mercedes-Benz investigate this issue promptly, acknowledge it as a known concern, and provide an appropriate inspection and repair at no cost to us. We love the brand and have always trusted its engineering and safety standards, which makes this experience especially distressing. We would greatly appreciate your immediate attention and a clear response on next steps.

Entire electrical system went out while driving causing check engine light to come on after the failure of system; there was no dashboard working at all when the system went out; without the dashboard out it was not certain if the vehicle was safe to drive anymore; the dealer has not been able to reproduce the problem; the vehicle has been with the dealer repair system for several weeks and have not been able to determine what happened; they have indicated that the vehicle had some type of water intrusion which short circuited the electrical system; the believes that the water entered into from the windshield area with a possible clogged water drain; there was no prior warning

I purchased this vehicle in May 28 2025. I certified car. I took in for oil change Nov 17-2025. Found out they had lot of issues., left front bushing arm leaking. Rt engine mount leaking. Bad brakes battery low. Bad tire rt back passage side.front wheel axle and rear wheel axle is bad and screw on the engine mount is missing. Screw and leaking..?and the vehicle needed a alignment.

The contact owns a 2021 Mercedes-Benz GLB250 equipped with Continental Tires, Tire Line: ProContact GX SSR, Tire Line: 235/55/R18, DOT Number: A33LWXX41220. The contact stated while driving 70 MPH, the vehicle began to vibrate with a flapping sound coming from the vehicle. Despite the failure, the contact was able to drive the vehicle to the residence. The contact then drove the vehicle to an independent mechanic where three humps were discovered on the front driver’s side tire that had formed due to thread separation on the inside of the tire. The mechanic referred the contact to a dealer who then referred the contact to the Continental tire manufacturer. The manufacturer informed the contact that the tire should be sent to the headquarters for an inspection. The tire was replaced. The failure mileage was approximately 30,600.

Seat belt failure.Driver side…mechanism… it feels unsafe…the retractor is not locking