Functional check

Remove vacuum hose of combination valve to be checked and connect VAG 1390 vacuum pump to combination valve.

Fig 1: Removing Vacuum Hose Of Combination Valve
Courtesy of AUDI OF AMERICA, INC.
Pull hose from Secondary Air Injection (AIR) pump motor and blow in with light pressure (do not use pressurize air).
Operate hand vacuum pump.
- The relevant combination valve must open, it must not possible to blow through
If the relevant combination valve does not open:
Replace combination valve

Fig 2: Connecting VAG 1390 Vacuum Pump To Combination Valve
Courtesy of AUDI OF AMERICA, INC.

If the relevant combination valve opens:
Repeat function test at second combination valve.

NOTE: