Volkswagen Golf / Golf GTI / Jetta. Manual - part 216

24-118

 

  

  

Note:  

  

  

All functions which could previously 
be performed with VAG 1551/1552 
can also be performed with the VAS 
5051. 

    

Checking function  

 VAG 1390 Hand vacuum pump 

-  Start engine and run at idle 

speed. 

   Actuator (vacuum unit) on intake 

manifold holds change-over barrel 
in position for long intake channel. 

    

-  Have a second person press 

accelerator pedal down fully onto 
limit stop (throttle burst). Observe 
vacuum unit for Intake Manifold 
Change-Over Valve -N156- 
(location: on left of intake 
manifold). 

   Actuating element must rotate 

barrel in intake manifold (arrow). 

-  Switch off ignition. 

Components, checking

24-119

 

  

  

If the actuating element does not perform the 
change-over sequence:  

  

  

-  Check activation of Intake Manifold Change

Over Valve -N156- via Output Diagnosis Test 
Mode (DTM) 

 

Page 01-100

 . 

  

  

If activation is OK:  

  

  

-  Connect scan tool. 

    

-  Pull vacuum hose -1-off non-return valve 

-  Connect hand vacuum pump VAG 1390 to non

return valve -2-. 

    

-  Perform Output Diagnosis Test Mode (DTM) 

again. When Intake Manifold Change-Over 
Valve -N156- valve is activated, operate hand 
pump uniformly. 

   Actuating element must switch back and forth 

between both positions. 

Components, checking

24-120

 

  

   If the change-over does not function as 

described:  

  

  

-  Check change-over mechanics for freedom of 

movement. Move rods by hand. 

  

  

-  Check vacuum pipes for correct connection. 

  

  

-  Check vacuum system including vacuum 

reservoir. 

  

   Note:  

  

   The vacuum reservoir is bolted below the intake 

manifold. 

Components, checking

24-121

 

  

  

Intake Air system, leak testing

 

  

  

Checking with engine leak detector spray G 
001 800 A1  

  

  

Note:  

  

  

 The vacuum in the intake system will cause the 

leak detector spray to be drawn in with the 
unmetered air. The leak detector spray reduces 
the ignitability of the mixture. This leads to a 
drop in engine speed and to a change of 
Oxygen Sensor (O2S) reading. 

  

  

 The safety precautions listed on the container 

must be adhered to. 

  

  

Special tools, materials and equipment  

    

Note:  

All functions which could previously be performed 
with VAG 1551/1552 can also be performed with 
the VAS 5051. 

 VAG 1551 Scan tool (or VAG 1552) with VAG 

1551/3 adapter cable 

 Engine leak detector spray G 001 800 A1

Components, checking