Volkswagen Workshop Service and Repair Manuals

Special tools, testers and auxiliary items

• ◆ Hand vacuum pump V.A.G 1390
• ◆ Vacuum tester V.A.G 1368

Test conditions

• ● Ignition switched off

Checking activated charcoal filter

• ‒ Remove air cleaner

=> Repair group 24; Motronic injection and ignition system

• ‒ → Pull off activated charcoal filter breather hose -1- on solenoid valve -2-.
       A - Solenoid valve engine code AEK
       B - Solenoid valve engine code AFT
• ‒ Connect hand vacuum pump V.A.G 1390 to hose -1-.
• ‒ Pull breather hose -3- from fuel tank off activated charcoal filter -4- and connect to -connection A- of vacuum tester V.A.G 1368.
• ‒ Connect vacuum tester V.A.G 1368 -connection B- to activated charcoal filter.
• ‒ Set vacuum tester to position -B-.
• ‒ Operate hand vacuum pump V.A.G 1390 several times.
       Vacuum must not
  build up.

If vacuum builds up:

• ‒ Check breather connection -5- on activated charcoal filter -4- for soiling, clean if necessary.

Checking lines to fuel tank and fuel cap

• ‒ → Pull breather hose -1- from fuel tank off at activated charcoal filter -2-.
• ‒ Connect hand vacuum pump V.A.G 1390 and vacuum tester V.A.G 1368 as shown to hose -1-.
• ‒ Set vacuum tester to -A/B- position.
• ‒ Remove fuel filler cap from filler neck.
• ‒ Operate V.A.G 1390 several times. Vacuum must
       not build-up.

If vacuum builds-up:

• ‒ Check gravity valve , item 28
• ‒ Check line -1- from fuel tank for blockage.

If vacuum does not build up:

• ‒ Refit fuel filler cap.
• ‒ Operate hand vacuum pump V.A.G 1390 several times.
       Vacuum must not
  build up.

Note:

If the fuel level in the tank is low the hand vacuum must be operated at least 20...30 times.

If vacuum builds up:

• ‒ Replace fuel tank cap.