Check Valve, Checking

WARNING: This page is about a different car, the 2021 Volkswagen Tiguan, 2020 Volkswagen Tiguan, 2019 Volkswagen Tiguan, and 2018 Volkswagen Tiguan. However, it is still accessible from the selected car via links, so may be relevant.

Inspection Process

-- Carefully remove the check valve with the vacuum line -1- from the brake booster.

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Blow some air first in one then in the other direction through the check valve -1-.

The check valve -1- must allow air through in direction of -arrow-.
The check valve -1- must remain locked in the opposite direction of the direction of -arrow-. If this is not the case, replace the check valve or the complete vacuum line.

NOTE:

Pay attention when installing that the vacuum line with the check valve is on correct installation position on the brake booster.