Page 20 of 46
24-90
      
Test requirements:  
     
Coolant Temperature at least 80  C. 
     
Fuse for oxygen sensor heating OK 
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations   
     
Test sequence  
    
Note:  
Coolant reservoir screws must be removed and coolant reservoir must be 
placed to side in order to access the harness connector. The coolant 
hoses can remain connected.  -  Disconnect 6-pin harness connector (black) -2- to Heated Oxygen 
Sensor (HO2S) -G39- before catalytic converter. 
    
If specified value is not obtained:  -  Connect multimeter between terminal 3 and 4 for resistance 
measurement. 
 
Specified value at room temperature: 2.5 to 10 
Pa
ge 20 of 46 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU07.24.2 
     
        
        Page 23 of 46
24-92
      
-  Operate starter briefly. 
     
 
Specification: approx. battery voltage
      If there is no voltage again:  
     
-  Check wire connection from terminal 3 of 
connector to Fuel Pump (FP) relay via fuse for 
open circuit: 
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations   
      If voltage supply is OK:  
    
Note:   -  Connect multimeter for voltage measurement as follows:Harness connector  
Terminal  
Measure 
to  
4 (Ground -GND- activation of Engine Control Module -
ECM-)  B+  
- Start engine.
 
Specification: approx. battery voltage
Pa
ge 23 of 46 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU07.24.2 
     
        
        Page 40 of 46
24-108
      
Test requirements:  
     
Coolant Temperature at least 80  C. 
     
Fuse for oxygen sensor heating OK 
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations   
     
Test sequence  
    
Note:  
Coolant reservoir screws must be removed and coolant reservoir must be 
placed to side in order to access the harness connector. The coolant 
hoses can remain connected.  -  Disconnect 4-pin harness connector -1- (brown) to Oxygen Sensor 
(O2S) behind Three Way Catalytic Converter (TWC) -G130-. 
    
If specified value is not obtained:  -  Connect multimeter between terminal 1 and 2 for resistance 
measurement. 
 
Specified value at room temperature: 6.4 to 47.5 
Pa
ge 40 of 46 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU07.24.2 
     
        
        Page 43 of 46
24-110
      
-  Operate starter briefly. 
     
 
Specification: approx. battery voltage
      If there is no voltage again:  
     
-  Check wire connection from terminal 1 of 
connector to Fuel Pump (FP) relay via fuse for 
open circuit: 
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations   
      If voltage supply is OK:  
    
-  Connect multimeter for voltage measurement as follows:Harness connector  
Terminal  
Measure 
to  
2 (Ground -GND- activation of Engine Control Module -
ECM-)  B+  
- Start engine.
 
Specification: approx. battery voltage, possibly fluctuating
-  Switch ignition off.
Pa
ge 43 of 46 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU07.24.2