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 InspectionShift And Select Mechanism [C66 M R]
Purpose, Function
The shift and select mechanism moves the shift fork to change gears according
to the operation of the shift lever in the cabin.
Construction
Shift control module
The moving parts of the shift control module are vertically positioned..
In th ...
Front Seat Back Trim Removal/Installation
WARNING:
Handling a side air bag improperly can accidentally operate (deploy) the
air bag, which may seriously injure you. Read the service warnings/cautions
in the Workshop Manual before handling the front seat (side air bag integrated)..
If the sliding mechanisms on both ...
Catch Tank
Purpose, Function
Suppresses pulsation occurring before evaporative gas is inducted into the
intake manifold.
Construction
The catch tank is installed in the engine compartment.
Operation
When evaporative gas flows from the charcoal canister to the purge sol ...