"Complaints allege the driver's frontal airbag deployed late and did not inflate properly," NHTSA said.
Federal safety regulators said they have received "two unusual but similar complaints of improper airbag deployment on 2013 Nissan Rogue vehicles."
In both instances, the complaints allege the driver's frontal airbag deployed as a result of a crash, but that the airbag "deployed many seconds (possibly up to a minute or so) after the crash," NHTSA said.
It added: "They also allege the airbag deployed slowly or did not fully inflate."
There are no injuries, crashes or fatalities linked to the probe.
"Nissan has not had an opportunity to inspect the two vehicles," wrote Nissan spokesman Steve Yaeger in response to a query from Edmunds. "Nissan is committed to a high level of customer safety, service and satisfaction. We will review this issue and, as always, work with the regulators to answer their questions."
Federal safety regulators have opened a preliminary evaluation into the matter. Such an action sometimes precedes a vehicle recall. But the 2013 Nissan Rogue has not been recalled at this point.
Edmunds says: Owners of these vehicles will have to wait until NHTSA finishes its investigation before taking any action. But if you have a concern about your 2013 Rogue in the meantime, get in touch with your Nissan dealer.