sensor AUDI A4 1999 B5 / 1.G AWM Engine Charge Pressure Leak Test Workshop Manual
Page 3 of 34
21-17
      
WARNING! 
     
Use only approved air fittings to adapt shop 
air supply line to VAG 1687 tester. 
     
Special tool VAG 1687/1 pressure adapter, 
installing (1.8L Turbo)  
     
-  Separate intake hose from Mass Air Flow (MAF) 
sensor assembly. 
    
Special tool VAG 1687/1 pressure adapter, installing (2.7L BiTurbo)  
 Repair Manual, Maintenance; Air cleaner housing, cleaning; Air cleaner element, replacing
    -  Insert VAG 1687/1 pressure adapter in intake hose -black arrow- using 
existing clamp (as shown). 
-  Remove crankcase ventilation tube from intake hose at -white arrow-.
-  Remove upper air cleaner housing and hoses to intake manifold as 
necessary 
    
-  Insert VAG 1687/1 pressure adapter in intake hose -white arrow- using 
existing clamp (as shown). 
-  Disconnect engine crankcase ventilation hose from intake manifold -
black arrow-. 
- 
Plug intake manifold fitting (for crankcase ventilation hose) with 
appropriate hose and metal plug using clamps supplied with VAG 
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11/21/2002 htt
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Page 30 of 34
21-39
 
  
Charge Air Pressure sensor -G31-, 
checking
 
Special tools and equipment  
 
VAG 1526 A
 VAG 1594 A
 VAG 1598/31
 VAS 5051 with VAS 5051/1
- or 
 VAG 1551 with VAG 1551/3 A
Pa
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11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2 
Page 31 of 34
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Test requirements:  
     
Vehicle diagnostic, testing and information 
system VAS 5051 or VAG 1551Scan Tool 
connected. 
     
Test sequence  
     
Note:  
     The Charge Air Pressure sensor -G31- and the 
wiring connections are monitored by the engine 
control module. 
     
-  Read Diagnostic Trouble Code (DTC) memory 
of engine control module. 
      If a DTC relating to the Charge Air Pressure 
sensor -G31- is displayed:  
     
Checking power supply  
    
-  Disconnect connector -arrow- on charge pressure sender.
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Page 33 of 34
21-42
 
    
If specified value is attained:  
Checking signal wire   -  Check for open circuit and short to positive or Ground in following 
wiring connections: Connector  
contact  
Test box VAG 1598/31  
1   108  
3   98  
-  Repair any open/short circuit as necessary.
-  Attach connector from charge air pressure sensor.
-  Attach multimeter for voltage test to socket 101 and socket 108 of test 
box. 
-  Start engine and run at idling speed.
Specified value: approx. 1.90 V 
-  Bring engine to speed by spontaneous acceleration.Specified value: 2.00...3.00 V 
Pa
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Page 34 of 34
21-43
       If specified values are not attained:  
    
If the wiring is OK:  -  Check for open circuit and short to positive or Ground in following 
wiring connection: Connector  
contact  
Test box VAG 1598/31  
4   101  
-  Repair any open/short circuit as necessary.
-  Replace Charge Air Pressure sensor -G31-.
Pa
ge 34 of 34 Char
ge pressure leak test with VAG 1687
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.GE06.21.2