WASHINGTON (Reuters) -The U.S. National Highway Traffic Safety Administration (NHTSA) said on Wednesday it is seeking records from electric car-maker Tesla in its investigation into Model 3 and Model Y vehicles over power steering loss reports.

The auto safety regulator, which upgraded its investigation in February, said in a letter dated Tuesday to Tesla and posted on its website that it wants Tesla's records by July 24 about the steering components.

The request includes Tesla's process for identifying problems and creating solutions for potential defects. The agency also wants to know whether Tesla has made any changes to power steering components or plans any in the next four months.

Tesla did not immediately respond to a request for comment on Wednesday.

The investigation covers about 334,000 Model 3 and Model Y vehicles from the 2023 model year and comes after the agency received 115 reports of loss of steering control.

The agency said the reports include steering or related failures, or steering becoming "stuck," "locked," or "immovable" or requiring high or increased effort. Other reports include "notchy" or "clicky" steering and steering-related error messages or warnings.

NHTSA, which had opened a preliminary evaluation in July 2023 into loss of steering control reports in 280,000 Tesla Model 3 and Y vehicles, said in February it identified a total of 2,388 complaints.

Reuters reported in December that tens of thousands of owners had experienced premature failures of suspension or steering parts since 2016, citing Tesla documents and interviews with customers and former employees.

The Tesla documents showed that the automaker sought to blame drivers for frequent failures of suspension and steering parts it has long known were defective, Reuters reported.

Some Tesla owners reported an inability to turn the steering wheel while others reported an increase in required effort. NHTSA said it is aware of over 50 vehicles allegedly towed as a result of the problem.

Tesla has had nine recalls in the United States for steering and suspension issues since 2018, NHTSA records show.