There are 1 stored owner reports matching the electrical system leading-label group for the 2021 Mercedes-Benz GLB-Class in our NHTSA-sourced dataset. These are unverified consumer reports and may not reflect confirmed defects.
This group counts stored reports whose component label starts with one of this site's matching prefixes, ignoring case. Each matching report counts once within the group. Components mentioned later in the label or only in the narrative are not searched. How component counts work
Loaded 1 of 1 matching reports.
Open the full vehicle complaint log (all categories)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.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
NHTSA source checks for this vehicle year
Checks are recorded separately for each dataset, not for the whole page. Dates use UTC. A missing check date does not mean no records exist.
Vehicle import recorded: Aug 31, 2026. This is the stored import date, not confirmation that every source was successfully refreshed.