Combination Valves, Checking

Diagnostic Procedures

Combination Valves, Checking

Test Conditions

• Vacuum lines and hose connections free of leaks.

• Vacuum hoses not clogged or kinked

• Pressure hose between combination valves and pressure hose for Secondary Air Injection (AIR) Pump Motors not clogged or kinked.

• Ignition switched off.

Test Sequence

Special tools, testers and auxiliary items required

• Hand vacuum pump (V.A.G 1390)





- Disconnect corresponding vacuum line of combination valve to be checked:

• Cylinder bank 1 combi-valve, refer to Repair Information.

• Cylinder bank 2 combi-valve, refer to Repair Information.

• Cylinder bank 1 with cylinders 1 through 6 is located at right in direction of travel.

• Cylinder bank 2 with cylinders 7 through 12 is located at left in direction of travel.

- Connect hand vacuum pump to corresponding vacuum connection of combination valve.

- Disconnect corresponding pressure hose from combination valve to be checked on Secondary Air Injection (AIR) pump motor:

• Vacuum hose from cylinder bank 1 combi-valve, refer to Repair Information.

• Vacuum hose from cylinder bank 2 combi-valve, refer to Repair Information.

• To disengage, compress the buttons at the hose coupling.

• Do not use compressed air during following check!

- Blow with light pressure into pressure hose. Both combination valves must be closed.

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

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

- Replace respective combination valve:

• Cylinder bank 1 combi-valve, refer to Repair Information.

• Cylinder bank 2 combi-valve, refer to Repair Information.

- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.