Subsequent work

Install pressure pipe -4- and air cleaner housing -3- . The instructions for installing the air cleaner housing -3- also covers installing the pressure pipe -4- . → WM 242519 Removing and installing air cleaner housing .

Fig 1: Identifying Air Cleaner Housing And Pressure Pipe
Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
Check vacuum using tester 9160/1.
1. 2.1. Tester 9160/1 (pressure gauge) must be connected. To do this, pull the adapter -2b- (or hose piece if an adapter -2b- is not used) together with the thin vacuum line out of the branch piece -2- of the vacuum line -1- .
  
  Fig 2: Checking Vacuum
  Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.
2. 2.2. Tester 9160/1 must be connected (plugged in) to the branch piece -2- .
3. 2.3. Start the engine and allow it to idle (engine speed is 650... 750 rpm/ambient temperature is 20°... 25° C). After a waiting time of approx. 10 seconds, read off the existing vacuum on the pressure gauge. Minimum value: 650 mbar.
4. 2.4. Then remove the tester 9160/1 and re-connect the adapter -2b- (or hose piece, if no adapter -2b- is used) to the branch piece -2- .