Testing the fuel cap

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2002 Volkswagen Jetta, 2002 Volkswagen GTI, 2001 Volkswagen Jetta, 2001 Volkswagen GTI, and 2000 Volkswagen Jetta. However, it is still accessible from the selected car via links, so may be relevant.

Remove fuel cap.

Fig 1: Testing The Fuel Cap

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Connect fuel cap receiver - arrow - to hose.
Screw fuel cap tightly to cap receiver.
Turn control valve to "Test" pressurizing cap.
Turn valve to "Hold".

Watch pressure gauge for drop in pressure from 14 inches H ₂ O.

If no pressure drop is indicated:

Proceed to Checking Leak Detection Pump (LDP) V144 for internal leaks.

If pressure drop is indicated:

Replace fuel cap and re-test.
Proceed to Checking Leak Detection Pump (LDP) V144 for internal leaks.