Diesel Exhaust Fluid (DEF) is a crucial component in modern diesel vehicles equipped with Selective Catalytic Reduction (SCR) systems. The SCR system utilizes this fluid to reduce nitrogen oxide (NOx) emissions into harmless nitrogen and water. These systems are legally mandated to meet stringent environmental regulations. If the DEF tank reaches empty, a series of consequences will occur.
The primary consequence of an empty DEF tank is a reduction in engine performance. Vehicles are programmed to enter a reduced power mode to discourage continued operation without the necessary emissions controls. This typically manifests as a decrease in speed and acceleration. Furthermore, the vehicle’s engine may eventually be prevented from starting altogether to ensure compliance with emissions standards. Ignoring DEF warnings and continuing to operate the vehicle can also potentially lead to damage to the SCR system itself, resulting in costly repairs.