There are 2 owner-reported air bags & restraints complaints for the 2021 BMW X4in NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
Went to sit in driver rear seat and put on my seat belt and found it frayed apart. Thought this was od and tried the rear passenger side only to find the exact same thing. Took it to the dealer in Visalia, CA. They said that they have never seen anything like that before. After discovering that both belts were broken in the same spot, they concluded it must be caused by wear in the retracting mechanism, but because the car was out of manufacturer's warranty they could only sell me new ones. I believe this is a very serious safety issue because as they were starting to fray apart the belts may have not had enough strength to restrain someone during an accident. Glad this was discovered before that happened!
BOTH rear seat belts have broken off in the same spot. Went to use the driver's side rear seat belt and found it had been broken (frayed off). Moved to the passenger side and found the exact same thing. This could have been a bad situation if in an accident had occurred where they had not completely frayed but would have failed. Took it to my local dealer and they had no answers as to how this could have happened but suggesting that it most likely happened inside the recoil mechanism. They offered no other remedy other than to have me pay for replacement since the car was out of manufactory warranty,
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.
Data synced from NHTSA on Apr 26, 2026