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 InspectionCamshaft Position (CMP) Sensor
Purpose/Function
Detects the camshaft speed as basic information for mainly determining the
fuel injection timing and ignition timing.
Detects the camshaft speed and inputs it to the PCM as a CMP signal.
Construction
Intake CMP sensor
Installed on the cylinder head.
...
Gear Position Indicator [Fw6 A EL, Fw6 Ax EL]
Purpose/Function
The gear position indicator illuminates while under manual shift control
and displays the gear number while driving.
Construction
The gear position indicator is built into the instrument cluster.
Operation
The TCM sends a gear position indic ...
Mass Air Flow (MAF) Sensor
Purpose/Function
Detects the intake airflow amount introduced into the cylinder as basic information
for mainly determining the fuel injection amount.
Detects the intake airflow amount introduced into the cylinder and inputs
it to the PCM as an intake airflow amount signal.
...