Malfunction Warning Mode: Description
WARNING: This page is about a different car, the 2016 Nissan Murano. However, it is still accessible from the selected car via links, so may be relevant.
In this function ECM turns on or blinks MIL when it detects a malfunction in the emission control system components and/or the powertrain control components (which affect vehicle emissions) to inform the driver that a malfunction has been detected.