Home · 2021 BMW 4 Series Gran · Complaints

What 15 owners told NHTSA about the 2021 BMW 4 Series Gran

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 (15)Electrical system (6)Engine (3)Seat belts (3)Tires (1)Transmission & drivetrain (1)

1 of 15 complaints match · Transmission & drivetrain · clear filters

Jul 22, 2024Transmission & drivetrain

The contact owns a 2021 BMW 430I. The contact stated while stopped at a traffic light, the light turned green; however, when the accelerator pedal was depressed, the vehicle failed to respond as intended. The contact stated that the power train warning light was illuminated. The contact turned off and restarted the vehicle, shifted to drive(D); however, the vehicle failed to respond. The contact had the vehicle towed to a dealer to be diagnosed. The dealer determined that the rear differential oil had leaked out causing the differential to seize. The contact was informed that the rear differential needed to be replaced. The vehicle was not repaired. The manufacturer was informed of the failure. The failure mileage was approximately 33,000.

NHTSA ODI 11603683

Working with the data? Download all 15 complaints as CSV · fetched from NHTSA July 20, 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 2021 BMW 4 Series Gran verdict →