Checking Brake Fluid Level and Leaks

WARNING: This page is about a different car, the 2005 Nissan Frontier. However, it is still accessible from the selected car via links, so may be relevant.

Check the brake fluid level in the reservoir tank. It should be between the "MAX" and "MIN" lines on the reservoir tank.
If the fluid level is extremely low, check the brake system.
If the brake warning lamp comes on when the fluid is at the correct level, check the brake fluid level switch and the parking brake switch.

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