Vacuum System, Checking

Vacuum system, checking

Checking solenoid valves for obstruction and leaks

- Remove intake manifold change-over valve or IMT valve 2.
- Disconnect connector from valve to be checked.







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

If a solenoid valve does not open.
- Replace intake manifold change-over valve or IMT valve 2.

If none of the checks already performed indicate a malfunction:
- Re-install relevant valve.
- Check vacuum system for leaks.

Checking vacuum system for leaks
- Disconnect vacuum hoses from relevant vacuum unit for intake manifold change-over.
- 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 does not have any leaks check all vacuum hoses for leaks.