The National Highway Traffic Safety Administration is investigating 50,000 Model X SUVs from 2022 and 2023 due to complaints from Tesla owners about the front belts not being properly connected at the factory.
The belt linkage and pretensioners, which are responsible for tightening the belts before a crash, are anchored to the seat frames, and both complaints allege that they separated from the frames while driving.
The NHTSA is investigating to determine the extent of the problem, how often it occurs, and whether Tesla's manufacturing processes are adequate.
The investigations can potentially lead to recalls of the affected vehicles, which is important to ensure the safety of Tesla's customers.
The NHTSA is also investigating complaints about problems with Teslas dating back to 2020, including issues with partially automated driving systems that can brake for no reason or run into emergency vehicles parked on highways.
There are also investigations into complaints about steering wheels suddenly disconnecting and suspension parts failing.
In February, Tesla issued a recall for nearly 363,000 vehicles with its "Full Self-Driving" system to fix problems with how it observes posted speed limits and behaves around street intersections.
The recall covers some 2016-2023 Model S and Model X vehicles, as well as 2013 through 2017 Model 3s, and 2020 through 2023 Model Y vehicles.