Vacuum System, Checking

Vacuum system, checking

Checking solenoid valves for obstructions and leaks

- Remove relevant intake manifold changeover valve.
- Disconnect harness connector from intake manifold change-over valve.







- Connect one of the contacts on the solenoid valve to engine Ground (GND) using test leads and alligator clip from VAG 1594 connector test kit.
- Connect other contact on solenoid valve to B+ using remote control VAG 1348/3A, adapter lead VAG 348/3-2 and auxiliary cable.
- Operate remote control VAG 1348/3A.
- By blowing into connection, check whether valve is opening properly.

If the valve does not open:
- Replace relevant intake manifold changeover valve.

If no malfunctions are identified in the tests performed up to this point:
- Re-install intake manifold change-over valve.
- Check vacuum system for leaks.

Checking vacuum system for leaks

- Disconnect vacuum hoses from relevant vacuum unit for intake manifold change-over system.
- Connect hand-held vacuum pump VAG1390 to vacuum unit.
- Operate hand-held vacuum pump and check whether change-over function is working.
- Check vacuum unit for leaks. (The vacuum unit should not return to the "rest" position while a vacuum is being maintained via the hand pump.)

If the vacuum unit returns to its "rest" position:
- Replace vacuum unit.

If the vacuum unit is airtight, check all vacuum hoses for leaks.