Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSAUDI2001A6 AVANT QUATTROREPAIR AND DIAGNOSISENGINE PERFORMANCESYSTEMEXHAUST SYSTEM, EMISSION CONTROL, GENERIC SCAN TOOL - 2.8L V6 AHA, ATQEXHAUST SYSTEM,EMISSION CONTROLSECONDARY AIR INJECTION (AIR) SYSTEMCOMBINATION VALVES, CHECKINGTEST SEQUENCE

2001 Audi A6 Avant Quattro

Test sequence

2001 Audi A6 Avant QuattroSECTION Test sequence

Disconnect vacuum hose of the combination valve to be checked at Y-piece (arrow).

Fig 1: Disconnecting Vacuum Hose Of Combination Valve
Connect VAG1390 hand vacuum pump to vacuum hose of the valve to be checked.

Fig 2: Connecting VAG1390 Hand Vacuum Pump To Vacuum Hose Of Valve

NOTE: Do not use pressurized air for the following test!

Remove front noise insulation.
Disconnect pressure hose (arrow) between Secondary Air Injection (AIR) Pump Motor and connecting line and blow into it with light pressure.

Fig 3: Disconnecting Pressure Hose

Both combination valves must be closed.

NOTE: To disengage, compress the buttons at the hose coupling.

Operate hand vacuum pump.
The respective combination valve must open.

If the combination valve does not open or it is constantly open:

Replace the respective combination valve. See COMBINATION VALVES, REMOVING AND INSTALLING .

RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.