2021 Mercedes-Benz GLB 250 4MATIC Problems
Owner-reported complaints filed with NHTSA, grouped by component
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What this page shows
Everything below is an owner-reported complaint submitted to NHTSA about the 2021 Mercedes-Benz GLB 250 4MATIC, 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
- Engine250.0%
- Electrical125.0%
- Fuel system125.0%
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
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.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Electrical
Reports naming the electrical system — wiring, battery, charging, control modules, infotainment and electrical accessories.
From owner reports, verbatim
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.
Too few reports in this category for a page of its own — they appear in the full complaint list.
Fuel system
Reports naming fuel storage or delivery — tanks, pumps, lines, injectors and fuel leaks.
From owner reports, verbatim
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
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 .