Pressure Retention Test

WARNING: This page is about a different car, the 2008 Volkswagen R32. However, it is still accessible from the selected car via links, so may be relevant.

-- Set the valve -D- to "Test". Increase the pressure up to 10 in. H2O (25 mbar).

Fig 1: Identifying Evaporative Emission (EVAP) Canister Purge Regulator Components

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Observe the pressure gauge -C- and flow meter -E-. The fuel system is filled if the flow quantity decreases and the pressure increases to 10 in. H2O (25 mbar).

NOTE:

Depending on the level in the fuel tank, this procedure may take up to 3 minutes.

-- After the pressure has stabilized, set the valve -D- to "Hold".

After 5 minutes the pressure must not drop below H2O (20 mbar) drop.

If the pressure is not maintained for 5 minutes, the leak should be localized as follows:

-- First check the EVAP canister purge regulator valve for leaks. Clamp off the hose to the EVAP canister purge regulator valve using the 3094.

Fig 2: Identifying Hose To Evaporative Emission (EVAP) Canister Purge Regulator Valve N80 Clamped Off With Hose Clamp

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Repeat the pressure test by resetting the valve -D- to "Test".

Fig 3: Identifying Evaporative Emission (EVAP) Canister Purge Regulator Components

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Observe the pressure gauge -C- and flow meter -E-. The fuel system is filled if the flow quantity decreases and the pressure increases to 10 in. H2O (25 mbar).

-- After the pressure has stabilized, set the valve -D- to "Hold".

-- If pressure now no longer falls, replace the EVAP canister purge regulator valve.

If the pressure still decreases, perform the "leak test in fuel system". Refer to FUEL SYSTEM LEAK TEST .

After completing the work, perform the "Check tank ventilation system for leaks".