Sept 12 (Reuters) - The U.S. National Highway Traffic

Safety Administration (NHTSA) has opened a preliminary

investigation into some electric vehicles manufactured by

Vietnam's VinFast, it said on Thursday, over reports that the

Lane Keep Assist System was not functioning correctly.

The investigation into about 3,118 VinFast vehicles came

after the regulator identified 14 reports from drivers of

VinFast 2023 and 2024 model years alleging that the system "has

difficulty detecting lanes on the roadway, provides improper

steering inputs, and is difficult to override by the driver",

NHTSA said in a statement.

The preliminary evaluation will assess the scope,

frequency, and severity of the potential problem and to

determine if a safety related defect exists in the subject

vehicles, NHTSA's Office of Defects Investigation said.

VinFast, which started selling vehicles in the United

States in 2023, did not immediately respond to a request for

comment. Its chairwoman said last year it sold fewer than 1,000

units in North America.

Earlier this year NHTSA also launched an investigation into

a crash on April 24 involving a VinFast, VF 8

electric vehicle in Pleasanton, California, in which four people

died.

A complaint filed with the agency on April 29 said steering

may have been an issue in the crash that killed a couple along

with their children aged 13 and 9.