My DVC light is on an it won't engage. Four wheel drive won't work. What would cause the dvc not to work

Hello, This issue is normally related to a bad ABS wheel speed sensor, but can be much ore serious. If you look at the wheel speed sensors and connectors, ensure they are not damaged, and make sure the connection is clean and dry (especially look for ice inside the connector). You very well may end up at the dealership, as the VDC system needs to be diagnosed with the Consult II system (proprietary to Nissan). You can get basic OBD-II codes with a regular code reader, and that may give you some insight into the issue.