FX45 AWD V8-4.5L (VK45DE) (2006)
Use a handy vacuum pump to check.
When connected to booster side (1): Vacuum decrease should be within 1.3 kPa (10 mmHg, 0.39 inHg) for 15 seconds under a vacuum of -66.7
kPa (-500 mmHg, -19.69 inHg)
When connected to engine side (2): No vacuum will be applied