July 31 (Reuters) - The National Highway Traffic Safety Administration said on Friday it has opened a preliminary investigation into about 1.2 million Tesla vehicles over reports of suspension failures that could cause a loss of steering control.

The regulator said its Office of Defects Investigation has received 156 complaints alleging the front lower lateral link detached in certain 2018-2020 Model 3 and 2021-2023 Model Y vehicles.

Tesla did not immediately respond to Reuters' request for comment. 

Most complaints indicated there was no advance warning before the failure, though some owners reported noises beforehand, and vehicles often had to be towed after the suspension detached, NHTSA said.

Reported failures extend beyond the scope of two previous Tesla recalls for lateral link detachments and do not appear to be related to the production issue addressed in those recalls, the regulator added. The preliminary evaluation will examine the underlying cause, scope and severity of the potential defect.