Vacuum System, Checking For Leaks

Vacuum System, Checking For Leaks
- Let engine run 2 to 3 minutes at idle (for vacuum to build up).
- Switch ignition off.
- Remove 2-pin connector from intake manifold tuning valve -N156- (change-over valve).







- Connect jumper wire (from VAG1594) from one terminal of -N156- to engine ground.
- Use VAG1248/3A remote, adapter wire VAG1348/3-2 and auxiliary wire to connect second terminal of -N156- to B+.
- Activate intake manifold tuning valve - N156-, using remote control VAG1348/3A, for approx. 2 to 3 min.
The vacuum solenoid must remain actuated during this time.

If vacuum solenoid releases, check solenoid as follows:
- Remove vacuum line from vacuum solenoid for intake manifold change-over.
- Connect VAG1390 hand pump to vacuum solenoid.
- Activate VAG1390 hand pump and watch change-over process.
- Check vacuum solenoid for leaks.
Vacuum solenoid should not return to initial position as long as vacuum is being applied by hand pump.

If vacuum solenoid returns:
- Replace vacuum solenoid.