24-55
      
Oxygen sensor heater, checking  
     
Notes:  
     
Z29 = Oxygen Sensor (O2S) heater, bank 1
     Z30 = Oxygen Sensor (O2S) heater, bank 2
     For functional check of O2S heater -Z29- or -
Z30-   Repair Group 01, Read measuring 
value block, display group 040 
     
-  Disconnect heated oxygen sensor harness 
connector (component locations   page 24
-1 ) 
    
If the specified value is not obtained:  -  Switch multimeter (Fluke 83 or equivalent) to 20 volt range and connect 
between terminals 1 (B+) and 2 (GND). 
-  Start engine and let idle. 
   Specified value: approx. 12 to 14 V
-  Check oxygen sensor heater fuse.
-  Check fuel pump relay   page 24
-24
 .
    
-  Check wiring for continuity between terminal 1 and fuse in fuse holder 
using wiring diagram, if necessary check terminal assignments. 
Pa
ge 5 of 7 Heated Ox
yg
en Sensor 
(HO2S
) after Three Wa
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ytic Converter 
(TWC
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11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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e=re
pair&id=AUDI.B5.FU01.24.13 
24-56
      
-  Check wiring for continuity between terminals 2 
and 8 on ECM connector E. 
     
  
Specified value: max. 1        
-  Check wiring for continuity between terminals 2 
and 3 of ECM connector E (O2S heater -Z30-). 
     
  
Specified value: max. 1         If the specified value is obtained:  
    
Note:  
With small increases in temperature, resistance will increase sharply. 
If the specified value is not obtained:  - 
Switch multimeter (Fluke 83 or equivalent) to measure resistance ( ) 
and connect between terminals 1 and 2.   
Specified value (room temperature): approx. 2 to 5 -  Replace heated oxygen sensor.
Pa
ge 7 of 7 Heated Ox
yg
en Sensor 
(HO2S
) after Three Wa
y Catal
ytic Converter 
(TWC
), 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.FU01.24.13