Pressure Retention Test

WARNING: This page is about a different car, the 2008 Volkswagen Jetta, 2008 Volkswagen GLI, 2007 Volkswagen Jetta, and 2006 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

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

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

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

-- Observe the pressure gauge -C- and the 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.

-- Check the EVAP canister purge regulator valve for leaks. Clamp off the hose to 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 the 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 the pressure now no longer falls, replace the EVAP canister purge regulator valve.

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

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