AutoUtility currently tracks 7 official NHTSA owner defect complaints for the 2021 Mercedes-Benz GLB. Engine & Cooling issues are the most frequently reported category, appearing in 2 complaints (28.6% of submitted records). Zero crashes, fires, injury reports, or fatality reports are cited across these complaint records.

Key Problem Findings
  • • Total NHTSA Complaints: 7 reports
  • • #1 Reported Problem Area: Engine & Cooling (2 reports • 28.6% of submitted complaints)
  • • Secondary Problem Areas: Fuel & Propulsion System (1), Electrical System (1)
  • • Crash-Citing Complaints: 0 filings
  • • Fire-Citing Complaints: 0 filings
  • • Complaints Reporting Injuries / Fatalities: 0 injury filings • 0 fatality filings
Reporting Methodology: Statistics describe unverified consumer submissions voluntarily filed with NHTSA. Complaint volume is not normalized for vehicle sales volume or miles driven. Multiple components can be cited within a single owner complaint submission.
Total Complaints
7
Submitted to NHTSA ODI
Crash-Citing Complaints
0
Filings citing a collision
Fire-Citing Complaints
0
Filings citing smoke or fire
Complaints Reporting Injuries
0
Filings citing one or more injuries
Complaints Reporting Fatalities
0
Consumer filings citing fatalities

Most Reported Problems for 2021 Mercedes-Benz GLB

Top automotive subsystem defect categories ranked by unique owner complaint volume in federal records

#1 Problem Area 28.6% of complaints

Engine & Cooling

2 owner complaints submitted to NHTSA ODI
✓ 0 crashes or fires cited
#2 Problem Area 14.3% of complaints

Fuel & Propulsion System

1 owner complaint submitted to NHTSA ODI
✓ 0 crashes or fires cited
#3 Problem Area 14.3% of complaints

Electrical System

1 owner complaint submitted to NHTSA ODI
⚠️ NHTSA Recall Context

NHTSA records list 2 official safety recall campaigns for this model year involving the same broad component area:

*Component overlap means an official recall exists for the same broad vehicle system. It does not establish that an individual owner complaint was caused by, covered by, or resolved through that recall.
✓ 0 crashes or fires cited
#4 Problem Area 14.3% of complaints

Powertrain & Transmission

1 owner complaint submitted to NHTSA ODI
✓ 0 crashes or fires cited
#5 Problem Area 14.3% of complaints

Suspension

1 owner complaint submitted to NHTSA ODI
⚠️ NHTSA Recall Context

NHTSA records list 2 official safety recall campaigns for this model year involving the same broad component area:

*Component overlap means an official recall exists for the same broad vehicle system. It does not establish that an individual owner complaint was caused by, covered by, or resolved through that recall.
✓ 0 crashes or fires cited
Domain Share Note: Share percentage represents the proportion of unique complaint filings referencing each vehicle system. Because single complaints may cite multiple systems (such as engine and electrical simultaneously), domain percentages represent individual category incidence and may sum to over 100%.

Recent NHTSA Owner Reports for 2021 Mercedes-Benz GLB

Representative defect filings submitted by owners to the NHTSA Office of Defects Investigation

Fuel & Propulsion System NHTSA ODI ID: #11753817
Filed: 07/30/2026

"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..."

Incident Date: 06/16/2026 • Raw NHTSA Component: ENGINE,FUEL/PROPULSION SYSTEM
Engine & Cooling NHTSA ODI ID: #11742901
Filed: 06/09/2026

"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..."

Incident Date: 05/22/2026 • Raw NHTSA Component: ELECTRICAL SYSTEM,ENGINE
Powertrain & Transmission NHTSA ODI ID: #11667631
Filed: 06/18/2025

"The contact owns a 2021 Mercedes-Benz AMG GLB35. The contact stated that while reversing down the driveway at approximately 4 MPH, the contact turned the steering wheel to the left and the vehicle started losing motive power. The contact stated that the RPMs were extremely high and the vehicle..."

Incident Date: 06/02/2025 • Raw NHTSA Component: SUSPENSION,POWER TRAIN
Engine & Cooling NHTSA ODI ID: #11660562
Filed: 05/12/2025

"On 4/13/25 while driving my car on the highway, along with my 2 young children, I began to hear what initally sounded like a "flapping" noise. I rolled the windows down and after a minute or 2 the sound got lounder. There was never a warning or any type of safety icon that appeared on the control..."

Incident Date: 04/13/2025 • Raw NHTSA Component: ENGINE
Brakes & Traction Control NHTSA ODI ID: #11638919
Filed: 01/27/2025

"The contact owned a 2021 Mercedes-Benz GLB35. The contact stated while driving at 35 MPH, the brake pedal was depressed; however, the vehicle failed to stop as intended. There was no warning light illuminated. The contact stated that neither the dealer nor an independent mechanic was contacted. The..."

Incident Date: 01/16/2025 • Raw NHTSA Component: SERVICE BRAKES, HYDRAULIC
Consumer Narrative Notice: Excerpts are sanitized text descriptions submitted by vehicle owners to the federal ODI database. They reflect the reporting consumer's observations at the time of filing and have not been independently confirmed by vehicle manufacturers or government investigators.

Complaint History for Mercedes-Benz GLB

Reported defect complaint volume across sibling model years (2020–2026)

Model Year NHTSA Complaints Crash Reports Safety Recalls Detailed Report
2020 Mercedes-Benz GLB 57 2 20 View 2020 Problems →
2021 Mercedes-Benz GLB Current Page 7 0 12 Current
2022 Mercedes-Benz GLB 13 2 1 View 2022 Problems →
2023 Mercedes-Benz GLB 12 0 1 View 2023 Problems →
2024 Mercedes-Benz GLB 0 0 2 View 2024 Problems →
2025 Mercedes-Benz GLB 0 0 2 View 2025 Problems →
2026 Mercedes-Benz GLB 1 0 1 View 2026 Problems →
Comparative Disclaimer: Complaint totals are unadjusted historical counts and are not normalized for vehicles sold, active fleet size, or total road mileage. Newer model years naturally have had less calendar exposure time to accumulate owner filings.

Detailed NHTSA Component Breakdown for 2021 Mercedes-Benz GLB

Complete distribution of consumer defect reports across all 7 granular NHTSA system and subsystem classifications

Vehicle Component / System Total Complaints Crash Reports Fire Reports Reported Injury Entries Reported Fatality Entries
ELECTRICAL SYSTEM,ENGINE 1 0 0 0 0
Engine NHTSA category: ENGINE 1 0 0 0 0
ENGINE,FUEL/PROPULSION SYSTEM 1 0 0 0 0
Service Brakes NHTSA category: SERVICE BRAKES, HYDRAULIC 1 0 0 0 0
SUSPENSION,POWER TRAIN 1 0 0 0 0
Visibility & Wipers NHTSA category: VISIBILITY/WIPER 1 0 0 0 0
Wheels & Hubs NHTSA category: WHEELS 1 0 0 0 0
Data Attribution & Reporting Methodology: Complaints are unverified voluntary submissions to the NHTSA Office of Defects Investigation (ODI). Because multiple vehicle components can be cited within a single owner complaint submission, component-level rollups may sum to more than the unique complaint count (7). Injury and fatality entries in the detailed table reflect raw values entered by reporting consumers across individual submissions; they are not deduplicated casualty statistics and may include duplicate or unverified entries. Complaint volume is not normalized for sales volume or vehicle mileage and does not represent an audited component failure rate.

Related Official Reports for 2021 Mercedes-Benz GLB

Cross-reference safety recalls, crash test safety ratings, and EPA fuel economy for this model year

Official US Government Data Provenance

The complaint records on this page are retrieved directly from the NHTSA Office of Defects Investigation (ODI) public database.

Local Production Store Compiled: August 2026 • Deterministic Audited Dataset • Zero Dynamic External API Runtime Latency.