1. Remove the vacuum hose..
2. Verify that air can be blown from the power brake unit side of the vacuum hose towards the vacuum pump side, and that air cannot be blown in the opposite direction.

If there is any malfunction of the inner check valve, replace it together with the vacuum hose as a single unit.
Vacuum Hose Removal/Installation
Vacuum Pump InspectionDSC Control
Outline
While a vehicle normally turns safely in response to steering operation,
there are instances when the limits of tire lateral grip is surpassed due to
road surface conditions or vehicle speed, and the influence of evasive steering
to avoid an accident or similar situations.
...
Auto Light Sensor
Purpose
The auto light sensor detects the illumination level above and in front of
the vehicle and outputs it to the front body control module (FBCM).
Function
The auto-light sensor uses the upward illumination level sensor to detect
the illumination level above the vehicle ...
Airflow Temperature Control [Full Auto Air Conditioner]
Purpose
The airflow temperature control changes the airflow temperature according
to the vehicle conditions.
Function
The air mix actuator is driven and the air mix door position is changed according
to the set temperature and the vehicle environment.
The climate co ...