Combination Valve for Secondary Air Injection (AIR), Checking Function

WARNING: This page is about a different car, the 2006 Audi A4, 2005 Audi A4, 2004 Audi A4, 2003 Audi A4, and 2002 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

The following procedure is used to test all combination valves.

Special tools, testers and auxiliary items required

Hand vacuum pump

Test conditions

Vacuum lines and hose connections free of leaks.
Vacuum lines not plugged.

Test procedure

Perform a preliminary check to verify the customers complaint. Refer to → Preliminary Check .

Start diagnosis

Remove the vacuum hose from the combination valve.

Fig 1: Hand Vacuum Pump V.A.G 1390 Connected To Combination Valve Vacuum Connection

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Connect the hand vacuum pump to combination valve vacuum connection.

Fig 2: Identifying Secondary Air Injection Hose

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Disconnect the Secondary Air Injection hose - arrow -.
Inject a light air pressure into the in Secondary Air Injection hose to close the combination valve. (do not use compressed air).

The combination valve should close and seal. Air should not be able to pass through the combination valve.

Operate the hand vacuum pump.

The combination valve should open. Air should be able to pass through the combination valve.

If combination valve does not open:

Replace the faulty combination valve. Refer to 26 EXHAUST SYSTEM, EMISSION CONTROLS .

End of procedure.