2021 Mercedes-Benz GLB Problems: 12 Known Issues

On the 2021 Mercedes-Benz GLB, mercedes-Benz determined that a number of Model Year 2021 GLB-Class (X247) vehicles may have left the plant with a driver airbag module that does not conform to specification. Because the module is not to spec, correct deployment behavior in a crash cannot be assured, which is a direct occupant-protection defect rather than a nuisance fault. Nothing about the condition is visible or detectable by the driver - there is typically no airbag warning lamp and no stored fault code - so the only way to know a vehicle is affected is a VIN check against the campaign. This is separate from the eCall and ESP campaigns that also hit the 2021 GLB.

On the 2020-2021 Mercedes-Benz GLB 2.0L turbo I4 (M260), an error in the communication module's embedded SIM-card software can cause a loss of mobile-network connection on GLB-Class vehicles, which disables the automatic emergency call (eCall / Mercedes me emergency) function. In a crash the vehicle may fail to automatically alert emergency services, and connected services may stop working. This is relevant in the EU where eCall is mandated. Covered by NHTSA recall 22V365 (a Mercedes campaign spanning 2017-2022 models, including the 2020-2021 GLB 250 and 2021 AMG GLB 35).

On the 2021 Mercedes-Benz GLB, on certain 2021 GLB (X247) vehicles the ride-height level sensor linkage at the rear axle - the input the automatic headlamp leveling system uses to work out how far the tail has squatted - was not installed correctly at the factory. With the linkage mounted wrong, the system reads the load backwards: when the third row, rear seat, or cargo area is loaded and the rear of the vehicle sits down, the headlamp leveling motors tilt the beams UP instead of down. The result is significant glare toward oncoming traffic exactly in the loaded, family-hauling condition the GLB's optional third row invites. Mercedes-Benz AG decided on the recall May 2, 2022, notified dealers May 16, 2022, and mailed owner letters June 10, 2022.

On the 2021 Mercedes-Benz GLB 2.0L turbo I4 (M260), recall 22V679 directly covers four model-year 2021 GLB 250 vehicles whose ESP control units may have been mechanically damaged during logistics. Moisture can enter the unit and disable functions including anti-lock braking and electronic stability control; a thermal event also cannot be ruled out. Warning messages or lamps may appear when the condition occurs. The four-vehicle recall population is not an owner-report count.

On the 2021-2025 Mercedes-Benz GLB M260 AMG, aMG GLB35 owners report a loud squeal from the brakes when coming to a stop under light pedal pressure, present from delivery and persisting well past the break-in period. Mercedes-Benz attributes the noise to friction between the brake lining (pad) and the brake caliper at their contact points. Mercedes-Benz has issued a technical service bulletin (LI42.10-P-075968) covering squeaky front brakes on the GLA35/GLB35, confirming this is a factory-known condition rather than a one-off. Owners who accepted the common dealer answer that it is 'normal for a performance pad' generally still had the noise; those who got the TSB applied did not. GLB250 owners separately report rear rotor surface corrosion and early rotor replacement, a related low-mileage brake complaint on this platform.

On the 2020-2022 Mercedes-Benz GLB 2.0L turbo I4 (M260), mercedes-Benz extended the exhaust-valve-system warranty to 15 years or 150,000 miles for certain model-year 2020-2022 GLB 250, GLB 250 4MATIC and AMG GLB 35 vehicles. The notice identifies valve-guide and/or seat-ring wear from increased lateral forces, which can cause cylinder misfires and an illuminated malfunction indicator lamp. Manufacturer communication 11028267 separately identifies a leaking valve seat, requires cylinder leakage testing and calls for complete cylinder-head replacement only when valve-seat damage is confirmed. Coverage and parts are VIN-specific; neither document establishes a universal manufacturing defect, owner-frequency rate or automatic cylinder-head replacement.

On the 2020-2024 Mercedes-Benz GLB, like other Mercedes direct-injected turbo engines, the M260 in the GLB (and the 1.3L M282 in the GLB 180/200) accumulates carbon deposits on the intake valves and intake tract over time because fuel is injected directly into the cylinder and never washes the back of the valves. This leads to unstable idle, hesitation, reduced power and worse fuel economy as mileage climbs, and German sources note the 1.3L can also develop coked injectors. It is a wear/maintenance issue, not a recall.

On the 2020-2021 Mercedes-Benz GLB 2.0L turbo I4 (M260), recall 21V990 directly covers 21,219 model-year 2020 GLB 250 vehicles and 6 model-year 2021 AMG GLB 35 vehicles whose front-axle integral carrier may have insufficient corrosion protection. After several years and under specific environmental influences, corrosion may impair structural durability or connections to other components, potentially affecting steering and increasing crash risk. The recall reported no warning inherent to the failure mechanism and no field complaints at the time; 21,219 is a recall population, not an owner-report total.

On the 2020-2021 Mercedes-Benz GLB 2.0L turbo I4 (M260), recall 22V232 directly covers 15,787 model-year 2020-2021 GLB 250 vehicles and 177 model-year 2021 AMG GLB 35 vehicles whose rearview-camera software may fail to show the required image after reverse is selected. The center display may instead retain the previous image or show a black screen with an inoperability message; the recall explicitly says the rearview image does not deactivate or freeze. These population counts are not owner reports.

On the 2020-2025 Mercedes-Benz GLB, the MBUX system freezes, reboots, or displays glitches. Apple CarPlay and Android Auto connections trigger instability in the head unit, and the voice assistant ("Hey Mercedes") intermittently stops responding.

On the 2020-2025 Mercedes-Benz GLB 2.0L turbo I4 (M260), the 8G-DCT dual-clutch transmission exhibits shudder and hesitation during low-speed maneuvers and from a standstill. While improved over the earlier 7G-DCT, the 8G-DCT still uses a wet clutch design that can judder when the clutch packs wear or the software calibration is outdated.

On the 2020-2025 Mercedes-Benz GLB, the panoramic sunroof develops creaking and popping noises, particularly in temperature extremes and over rough roads. The large glass panel flexes differently than the metal roof structure, creating friction at the seal interfaces.