SEAT Workshop Service and Repair Manuals

Checking fuel tank breather

Special tools and workshop equipment required

t	Vacuum tester -V.A.G 1368-

t	Adapter -SAT 1368/1-

t	Hand vacuum pump -SAT 1390-

Test sequence Part I (AEH, AKL engines)

–  Pull breather pipe/hose -2- from activated charcoal filter -1- off at throttle valve control part -3-. –  Connect hand vacuum pump -SAT 1390- to pipe/hose -2-. –  Pull breather pipe/hose -5- from fuel tank off activated charcoal filter and connect to connection -A- of vacuum tester -V.A.G 1368-, to use adapter -SAT 1368/1-. –  Connect vacuum tester -V.A.G 1368- connection -B- to breather pipe/hose -4-, to use adapter -SAT 1368/1-. –  Set vacuum tester to position -B-. –  Introduce final control diagnosis and select activated charcoal filter solenoid valve -N80-: → Diagnostics operations unitVAS 5051. –  Operate hand vacuum pump -SAT 1390- several times. Vacuum must not build-up. If vacuum builds-up:

–  Check breatehr connection -6- on activated charcoal filter -1- for soiling, clean if necessary. If vacuum does not build-up: –  Remove fuel filler cap.

–  Connect hand vacuum pump -SAT 1390- to vacuum tester -V.A.G 1368- connection -B-. –  Set vacuum tester to -A/B- position. –  Operate -SAT 1390- several times. Vacuum must not build-up. If vacuum builds-up: –  Check gravity valve → Item.

–  Check pipe/hose -1- from fuel tank for blockage. If vacuum does not build-up: –  Refit fuel filler cap. –  Operate hand vacuum pump -SAT 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. Part II (Engines APF, AUR) Check conditions l  Fuel tank deaeration valve checked and test OK → Diagnostics operations unitVAS 5051.   Note! Thist test checks the pipes from the throttle control unit to the aeration connection of the activated charcoal filter. Testing process

–  Remove the ventilation line -1- that goes from the fuel tank to the activated charcoal filter and connect it to the -V.A.G 1368- descompression tester socket -A-; to do so, use the -SAT 1368/1- adapter. –  Unscrew the cap of the fuel tank filler hole. –  Connect the -SAT 1390- manual vacuum pump to the -V.A.G 1368- descompression tester socket -B-. –  Set the descompression tster in the position -A/B-. –  Activate the -SAT 1390- several times. There should be no descompression. If there is descompression: –  Check the gravity valve → Item.

–  Check the continuity of the flow of the fuel tank line -1-. If there is no descompression: –  Screw on the fuel tank filler hole cap. –  Activate the -SAT 1390- manual vacuum pump several times. There should be no descompression.   Note! If the fuel level in the tank is low, the manual vacuum pump should be activated approx. 20…30 times. If there is descompression: –  Replace the cap of the fuel filler hole.