NHTSA opens probe into 115,000 Rivian R1T and R1S vehicles (picture alliance / Getty Images)The National Highway Traffic Safety Administration opened a preliminary investigation on Thursday into 114,922 Rivian R1T and R1S electric vehicles over a potential defect in the rear toe link suspension component.Two complaints from vehicle owners — each describing a left rear toe link that gave way while driving, sending their vehicles veering across several lanes — prompted NHTSA to act, according to Reuters. In one of the two cases, the loss of control ended with the Rivian striking both a nearby car and a roadside barrier.Mounted between the wheel hub and the vehicle chassis, the rear toe link is a suspension rod that helps maintain wheel alignment, according to Bloomberg. Among its planned steps, NHTSA intends to examine the component's durability under typical road and service conditions and review whatever repair procedure Rivian currently has in place.AdvertisementAdvertisementWhile acknowledging it is working with NHTSA, Rivian disputed the premise of the inquiry, saying its internal review found no evidence that the toe link was responsible for either incident, according to Bloomberg. "Rivian data indicates R1 toe link joints are operating as intended," the company said.This is not Rivian's first toe link problem: earlier this year the company issued a recall covering close to 20,000 R1S and R1T owners whose vehicles had been previously serviced with improperly assembled hardware. Replacement bolts were provided at no cost to affected owners.Rivian reported first-quarter revenue of $1.38 billion, up 11% year over year, and posted its third consecutive quarter of positive gross profit. The company reaffirmed full-year delivery guidance of 62,000 to 67,000 vehicles, with production of the lower-priced R2 SUV now underway at its Normal, Illinois, facility. The R1T and R1S — each priced above $70,000 — remain Rivian's primary revenue vehicles as R2 volume builds through the back half of the year.The NHTSA investigation does not cover R2 vehicles, which are not included in the 114,922-unit probe scope.