The recall covers vehicles from 2019-22 model years and affects a total of 271,694 vehicles in the U.S.
Subaru is advising owners of these Ascent models to park their vehicles away from structures such as garages and avoid leaving their vehicles unattended with the engine running.
The Japanese automaker on Friday said a ground bolt that secures the ground terminal of the Positive Temperature Coefficient heater may have been improperly fastened during vehicle production.
"This potential condition may result in the melting of the ground terminal and surrounding components, increasing the risk of fire when the PTC heater is in operation," the automaker said.
There have been no crashes or injuries related to the issue.
To fix the issue, Subaru dealers will replace the ground bolts. They also will replace the ground wire and connector holder, as necessary.
Owners will be notified by mail in 60 days.