LINE, Diesel Exhaust Fluid Pressure: Description: Description
WARNING: This page is about a different car, the 2011 RAM Pickup and 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The Diesel Exhaust Fluid (DEF) pressure line supplies fluid from the pump to the injector and has connectors similar to fuel lines. The line also incorporates a heater to keep the DEF fluid from freezing.