Before it becomes a recall, it's an investigation. The National Highway Traffic Safety Administration (NHTSA) is currently investigating theutility vehicle for an issue related to its exhaust system, and whether or not fumes are entering the cabin.
The NHTSA is taking a look at 2011-2015 Ford Explorers after it received 154 complaints of exhaust smells in the passenger compartment. Some complainants expressed concern about carbon monoxide exposure. From the complaints, it appears that the smell may occur during full throttle events, or when the air conditioning is on and the HVAC system is set to recirculation mode.
Ford issued two technical safety bulletins (TSBs) that appear to relate to this issue. One specifies sealing and coating the rear floor pan and body seams, as well as replacing an air extractor and installing drain valves, and the other adds software changes to the mix. A TSB alerts service departments to an issue and explains how to potentially remedy said issue. Not all TSBs are related to recalls or investigations.
NHTSA's site points out that some owners reported no change in driving experience following the TSB. A Ford spokeswoman replied to me via email: "We will cooperate with NHTSA on this investigation, as we always do."