Air Bypass Valve: Testing and Inspection

Deceleration strut-off valve, checking
Special tools and equipment





^ VAG1390 hand vacuum pump

Test requirement
- Performance deficiency or tip-in shocks

Test sequence

Note: The deceleration shut-off valve is located in front of the turbocharger. It is opened by vacuum during deceleration and at idle.





- Connect VAG1390 hand vacuum pump to vacuum connection for deceleration shutoff valve.
- Operate hand vacuum pump. Deceleration shut-off valve must open (arrow).
- Operate ventilation valve at vacuum pump. Deceleration shut-off valve must close (arrow)
If deceleration shut-off valve does not open or does not close, replace valve.

Note: Secure connections of deceleration valve using screw-type clamps.