Checking Brake Fluid Level

WARNING: This page is about a different car, the 2006 Infiniti G35. However, it is still accessible from the selected car via links, so may be relevant.

Check fluid level in reservoir tank. It should be between Max and Min lines on reservoir tank.
If fluid level is extremely low, check brake system for leaks.
Release parking brake lever or pedal, and then see if brake warning lamp goes off. If not, check brake system for leaks.

Fig 1: Checking Brake Fluid Level
Courtesy of NISSAN MOTOR CO., U.S.A.