Pressure Retention Test

-- Set valve -D- to "Test". Increase the current pressure until it reaches 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-. If the flow quantity decreases and pressure increases to 10 in. H2O, then the fuel system is full.

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

• After 5 minutes the pressure must not drop below 8 in. H2O (20 mbar).

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

-- First, check the EVAP canister purge regulator valve 1 for leaks. Clamp off the hose to the EVAP canister purge regulator valve 1 using a hose clamp up to 25 mm dia.3094 -arrow-.

Fig 2: Clamping Off Hose To EVAP Canister Purge Regulator Valve 1 -N80- Using Hose Clamps Up To 25 Mm Dia. 3094

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Repeat the pressure test by resetting 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-. If the flow quantity decreases and the pressure increases to 10 in. H2O, then the fuel system is full.

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

-- If the pressure now no longer falls, replace the EVAP canister purge regulator valve 1.

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" guided function using the vehicle diagnostic tester.