The National Highway Traffic Safety Administration has launched an investigation into multiple reports of “catastrophic engine failures” at speed in 2021 models, the .

The National Highway Traffic Safety Administration said in a filing made public this week that it was opening a formal investigation into a series of reports involving 2021 Ford Bronco SUVs that experienced loss of power at highway speeds. The probe covers nearly 25,500 vehicles, NHTSA said.

NHTSA said it had been weighing whether to open an investigation into the potential defect since late May, when the agency said it received multiple petitions from Bronco owners about the alleged defect. In a meeting last month with Ford Motor, NHTSA staff learned the alleged loss of power is a result of catastrophic engine failures due to the engine valves failing, the agency said in the filing.

This action comes after from Bronco owners were submitted to the NHTSA’s Office of Defects Investigation. “Some have barely avoided major injury when their vehicles have had complete power loss at freeway speeds in traffic,” one owner petition reads. According to NHTSA, no accidents or injuries have been linked to the alleged engine failures.

Ford has reportedly honed in on the “root cause,” per WSJ, but did not respond to the publication’s request for comment:

Ford identified the root cause of the alleged defect as interference between the valve and piston within the 2.7-liter EcoBoost engines, which can result in the engine locking up, NHTSA said. The regulator has identified 26 reports that related to the alleged defect in the Bronco.

Jalopnik also contacted Ford for comment, and we will update this article with any reply we receive.

Ford Communications Manager Jiyan Cadiz responded to Jalopnik with the following statement:

We are aware of a select number of engines early in the launch that exhibited this concern and we are investigating. If any customers are experiencing issues, they will be covered under the vehicle’s 5-year, 60,000 mile powertrain warranty. We will cooperate with the NHTSA as we always do.

The Bronco comes standard with a 300-hp 2.3-liter EcoBoost turbo four-cylinder engine; the 330-hp 2.7-liter twin-turbo V6 at the heart of this defect investigation is an optional upgrade engine (standard on the top-trim Wildtrak model). NHTSA states as many as 25,538 vehicles may be at risk of the defect, where the pistons can collide with the valves and cause total engine failure at speed.

As of yet, Ford has not announced a recall campaign, though this investigation may very likely be the preamble to one. This, unfortunately, is not at all a new routine for Ford as of late, which has had to announce across much of its lineup, particularly as the company has ramped up manufacturing of its most highly anticipated new models, like the , and, of course, the Bronco.