2021 MERCEDES-BENZ GLB 250 Complaints

The contact owns a 2021 Mercedes-Benz GLB250. The contact stated that the front stationary roof panel detached from the vehicle and shattered. The vehicle was taken to the dealer but was not diagnosed or repaired. The contact became aware of a recall with a similar failure; however, the VIN was not included, and the model year was not included in a recall for the failure. The manufacturer was not made aware of the failure. The failure mileage was approximately 63,000.

As I was driving down road car began to lose power, check engine light came on and car went into limp mode. Car was towed to nearest repair shop where analysis was made. I was advised to take to dealership for repair. Advised that there was a service campaign issued by the manufacturer on GLB class with M260 motors. See attached report. Took car to MB dealer and informed that an update to the ECU was needed but not available at this time. See attached report. Returned home to PA called Mercedes main office Customer service to check warranty and coverage yes it covered once dealer verifies codes. Called NHTSA to report where they verified that the manufacturer had agreed to repair the issue and extended the waranty instead of doing a recall. Was advised to file report online because the dealership is now demanding payment to do the software update. Which was already verified see attached. A rail pressure sensor is a core engine management component that measures fuel pressure in the fuel rail, sends real-time data to the engine computer, and helps regulate fuel delivery. Rail Pressure Sensor system Fault code P019185 Stores in MED41 control unit. Available for Inspection

While driving on the highway at 70mph my transmission malfunction warning light illuminated in red and my vehicle went into limp mode, creating a life threatening safety defect at highway speeds. I immediately took the vehicle to Mercedes Benz of Pittsburgh. The dealer's own diagnostic tech notes stated 'software is in preparation for concern' confirming this is a known safety defect on Mercedes' end. The dealer was unable to replicate the concern or produce stored fault codes but acknowledged software is actively being developed to address this issue. I contacted MBUSA who confirmed the only escalation path available is a buyback, meaning Mercedes cannot provide a timeline for the software fix. I am currently unable to safely drive my vehicle and am requesting this be investigated as a potential safety defect that may affect other 2021 Mercedes GLB 250 owners.

Family and I were driving on the interstate and heard a loud bang (like a shotgun) followed by immediate glass everywhere. The panoramic sunroof exploded. We had to drive 4 hours like this - lucky we didn’t jerk the wheel on the interstate with the noise. Absolutely sickening that this is so prevalent and Mercedes won’t do anything about it.

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.

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.

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.

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.

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

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.