EGR Bypass Valve
WARNING: This page is about a different car, the 2018 Nissan Titan XD. However, it is still accessible from the selected car via links, so may be relevant.
The ECM uses this valve to allow exhaust gas into the engine without going through the EGR cooler (EGR cooler bypass). Some operating conditions require EGR that does not go through the EGR cooler, such as at start up (aids in warming a cold engine) or during regeneration of the Diesel Particulate Filter (DPF),