fuse diagram AUDI A4 1996 B5 / 1.G APB Engine Oxygen Sensor Control Checking Workshop Manual
Page 45 of 61
24-117
      
Checking voltage supply for oxygen sensor 
heater  
      Component location of 4-pin harness connector 
of oxygen sensors   Page 24
-5 .  
     
-  Check fuse for oxygen sensor heater
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations        
-  Disconnect 4-pin harness connector of particular 
oxygen sensor. 
    
If there is no voltage reading:  -  Connect hand-held multimeter (voltage measurement range) between 
sockets 1 (B+) and 2 (Ground (GND)) using test leads from VAG1594 
connector test kit. 
-  Operate starter briefly. 
   Specified value: approx. battery voltage
-  Connect hand-held multimeter (voltage measurement range) between 
socket 1 (B+) and vehicle Ground (GND) using test leads from 
VAG1594 connector test kit. 
Pa
ge 45 of 61 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.FU04.24.2 
Page 46 of 61
24-118
      
-  Operate starter briefly. 
     
   Specified value: approx. battery voltage
      If there is still no voltage reading:  
     
-  Check for open circuit and/or short circuit in 
wiring between fuel pump relay and socket 1 on 
the relevant oxygen sensor connector (on wiring 
harness) via fuse. 
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations         If the voltage supply is OK:  
    
-  Connect hand-held multimeter (voltage measurement range) between 
socket 2 (switched Ground (GND) connection from engine control 
module) and B+ terminal using test leads from VAG1594 connector test 
kit. 
Pa
ge 46 of 61 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.FU04.24.2