Vacuum System, Checking

Vacuum System, Checking

Checking valve for obstruction and leaks

- Remove intake manifold change-over solenoid valve.
- Disconnect connector from relevant solenoid valve for intake manifold change-over.







- Connect one of contacts on solenoid valve to engine Ground using test leads and alligator clamp from VAG 1594.
- Connect second contact of solenoid valve with remote control VAG 1348/3A, adapter lead VAG 1348/3-2 and auxiliary cable.
- Operate remote control VAG 1348/3A.
- Blow into connection to check whether solenoid valve opens correctly.

If the solenoid valve does not open:
- Replace intake manifold change-over solenoid valve.

If none of the checks already performed indicate a malfunction.
- Re-install intake manifold change-over solenoid valve.
- Check vacuum system for leaks.

Checking vacuum system for leaks

- Disconnect vacuum hoses from vacuum unit for intake manifold change-over system.
- Connect hand vacuum pump VAG 1390 to vacuum unit.
- Operate hand pump and check whether changeover function is working.
- Check vacuum unit for leaks. (Vacuum unit should not return to rest position until hand pump is vented to atmosphere.)

If vacuum unit retracts:
- If necessary, replace vacuum unit.

If the vacuum unit is leak-free:
- Check all vacuum hoses for leaks.