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What 12 owners told NHTSA about the 2023 Mercedes-benz GLB

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (12)Engine (4)Transmission & drivetrain (3)Brakes (2)Visibility & wipers (2)Carry Handle, Shell, Base (1)Fuel system (1)Other/i Am Not Sure (1)

4 of 12 complaints match · Engine · clear filters

May 20, 2026Engine

Safety Risk - Twice I was almost hit because my car didn't take off. O'REILLY Veri Scan Results - Free Emissions Status: Red Primary DTC: Mixture Formation (Cylinder 4) is irregular P219F: Fuel injectors measure and atomize fuel mixed with incoming air and sent to combustion chambers. Cylinder 4 PSI at 40 Mercedes Benz of San Juan $300 diagnostic Cylinder head needs to be replaced. Safety Risk - Twice I was almost hit because my car didn't take off. Problem has been confirmed by dealer. Not inspected by manufacturer, etc. Prior to failure there were no signs. Check Engine light came on and that is when it got checked at 55, 715 miles, soon after warranty ended.

NHTSA ODI 11739111

Apr 27, 2026Transmission & drivetrainEngineFuel system

My 2023 Mercedes-Benz GLB 250 is experiencing engine misfires and fault codes consistent with a known cylinder head defect that is the subject of a recall affecting 2022 and earlier models. A certified mechanic has confirmed the issue aligns with the recall defect. Despite identical symptoms and engine configuration, my VIN is excluded. The condition results in loss of power and creates a potential safety hazard while driving. The following codes are referenced in the Mercedes recall and by recorded by the auto repair shop that provided an estimate for the repair: P1CEF85 - Injector injection quantity adjustment for cylinder balancing has almost reached the upper limit value at atleast one cylinder. P1CE577 - Injector injection quantity adjustment for uniform mixture formation has detected an excessively lean mixture at atleast one cylinder.

NHTSA ODI 11733918

Feb 26, 2026Engine

On December 19, 2025, the vehicle showed lights that a sparkplug had misfired. The dealer notified me that in less than two full years of having the 2023 vehicle, it required a complete engine rebuild. This is the third major engine problem I have had with the vehicle with more than $20K in fees. The services performed in December 2025 repairs included Cylinder Head Assembly to Replace Engine Cylinder Head Assemble due to multiple cylinder head fault codes, including misfire, injector injection, and mixture formation code. Cylinder 2 is leaking out of the exhaust valve. Camshaft replacement and rollers due to deep scoring on both intake and exhaust cams, not by cylinder two. Exhaust valve leaking from the head while the camshafts are scoring, leading to misfiring as well.

NHTSA ODI 11720803

Nov 11, 2025Engine

Cylinder repair dealership said it's a known issue but Mercedes Benz said they will not cover the repair.

NHTSA ODI 11698759

Working with the data? Download all 12 complaints as CSV · fetched from NHTSA July 18, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2023 Mercedes-benz GLB verdict →