WARNING: This page is about a different car, the 2007 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
CHECK VALVE SPECIFICATION
Vacuum leakage [at vacuum of -66.7 kPa(-500 mmHg, -19.69 inHg)]
Within 1.3 kPa (10 mmHg, 0.39 inHg) of vacuum for 15 seconds