Charge Air System With Turbocharger (Engine Code Atw)

Charge air system with turbocharger (engine code ATW)

Checking mechanical recirculation valve

Notes:
^ The mechanical recirculation valve is located in front of the turbocharger. It is opened by vacuum via the recirculating valve for turbocharger -N249- during deceleration, idle and part throttle. This produces a reduction of the boost pressure in front of the throttle valve which keeps the turbocharger spinning at a higher RPM.
^ Check the recirculation valve in case of reduced performance or part throttle hesitation.

Special tools and equipment





^ VAG1390

Test sequence





^ Attach VAG1 390 vacuum pump to recirculation valve.
^ Operate vacuum pump.
- Recirculation valve must open (arrow)

^ After approximately 30 seconds, operate vent valve on vacuum pump.
- Recirculation valve must close (arrow)

If recirculation valve does not open or close or valve plate does not seal correctly when valve is closed:
^ Replace recirculation valve. Secure connections of recirculation valve using screw type clamps.