DEF Dosing 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 DEF dosing valve is located on the decomposition tube. It is a PWM valve that sprays a fine mist of DEF into the exhaust stream when commanded by the ECM. This spray of DEF is sometimes called SCR dosing because the SCR catalyst uses DEF to chemically convert NOx to nitrogen and water.

Courtesy of NISSAN NORTH AMERICA, INC.