Functional check

WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 1999 Volkswagen Jetta, 1999 Volkswagen GTI, 1998 Volkswagen Jetta, 1998 Volkswagen GTI, and 1997 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

Check EVAP canister. See Checking EVAP canister .

NOTE: EVAP canister purge regulator valve is also checked during the EVAP canister check.

If vacuum does not build up:

Connect VAG 1598/18 test box to Engine Control Module (ECM) wiring harness.

Fig 1: VAG 1598/18 Test Box
Using VW 1594 adaptor kit, bridge test box sockets: 1 + 23, 1 + 31.
Operate US 8026/VAG 1390 vacuum several times. Vacuum must build up.

If vacuum does not build up:

Replace EVAP canister purge regulator valve -N80-.