Page 3 of 63
24-78
 
  
Oxygen sensors and oxygen sensor 
control before catalytic converter, 
checking
 
Special Tools and Equipment  
 
VAG1526A
 VAG1594A
 VAG1598/31
 VAS5051 with VAG5051/1
- or 
 VAG1551 with VAG1551/3B
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        Page 8 of 63
24-82
 Significance of 3 digit indication of display group 030  X  
X  
X  
Display fields 1 to 4  
      X   Oxygen sensor control  
0= not active  
1 = active  
   X      Operational readiness of oxygen sensor  
0= not active  
1 = active  
X         Condition of oxygen sensor heating  
0= not active  
1 = active  
Notes:  
 
The oxygen sensor control of the oxygen sensors behind catalytic converter (B1-S2 and B2-S2) are not active at certain 
operation points without engine load, that means that the third position of the oxygen sensor controls behind catalytic 
converter can fluctuate between 0 and 1. 
 The first position of the 3 digit indication (heating) fluctuates between 0 and 1 at certain operation points.
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        Page 10 of 63
24-84
 
   1   2   3   4  
Display group 033: Oxygen sensor control before catalytic converter  
Display  
xx.x %  x.xxx volts  
xx.x %   x.xxx V  
Indicated  
Oxygen sensor control
Bank1  Oxygen sensor voltage 
bank 1  Oxygen sensor control
Bank2  Oxygen sensor voltage 
bank 2  
Functional 
range  -25.0 to 25.0 %   0.100 to 1.000 V  
-25.0 to 25.0 %   0.100 to 1.000 V  
  
Specified 
value  Value must fluctuate by 
at least 2 % in the range 
10.0 to 10.0 %  Value must fluctuate 
approx. 0.3 V in the 
range 0.100 to 1.000 
volts  Value must fluctuate by 
at least 2 % in the range 
10.0 to 10.0 %  Value must fluctuate 
approx. 0.3 V in the 
range 0.100 to 1.000 
volts  
Notes  
If specified value is not 
obtained  Page 24
-85
   
  
If specified value is not 
obtained  Page 24
-85
   
  
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        Page 12 of 63

24-86
      
- Press -C- button. 
     
-  Press buttons -0-, -3- and -2- to select "display 
group number 032" and press -Q- button to 
confirm input. System in Basic Setting 32  
1 
2 
3 
4
    
When indicated on display:  
-  Check oxygen sensor control in display fields 1 to 4:
  
Display fields  
  
1   2   3   4  
Display group 032: Oxygen sensor adaptation values before catalytic converter  
Display  
xx.x %  
xx.x %  
xx.x %  
xx.x %  
Indicated  
Oxygen sensor 
adaptation value 
Bank 1 at idle  
(additive)  Oxygen sensor adaptation 
value bank 1 at partial 
throttle 
(multiple)  Oxygen sensor 
adaptation value 
Bank 2 at idle  
(additive)  Oxygen sensor adaptation 
value bank 2 at partial 
throttle 
(multiple)  
Functional 
range  -25.0 to 25.0 %  
-25.0 to 25.0 %  
-25.0 to 25.0 %  
  -25.0 to 25.0 %  
  
Specified 
value  -10.0 to 10.0 %  
can fluctuate 
slightly  -10.0 to 10.0 %  
can fluctuate slightly  -10.0 to 10.0 %  
can fluctuate 
slightly  -10.0 to 10.0 %  
can fluctuate slightly  
Notes  
If specified value is not obtained   Page 24
-87
   
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        Page 20 of 63
24-93
      
Oxygen sensor aging (oxygen sensor 
before catalytic converter), checking
 
     
Special Tools and Equipment  
    
VAG1788/10 RPM adjuster
    
Test requirement: 
VAS5051 with VAG5051/1
   orVAG1551 with VAG1551/3BCoolant temperature at least 80  C   Display group 4, display field 3
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        Page 22 of 63

24-95
 
  
Display fields  
  
1   2   3   4  
Display group 034: Oxygen sensor aging diagnostic, oxygen sensor before catalytic converter (bank 1)  
Display  xxxx/min  
xxx C  
x.x s  
---  
Indicated  Engine speed 
(RPM)  Exhaust 
temperature  Period duration  
Oxygen sensor before  
Catalytic converter  Diagnostic condition  
Functional 
range  630 to 6800  
70 to 850 C  
0 to 3.0 s  
Test OFF  
Test ON  
B1-S2 OK  
B1-S2 not OK  
Specified 
value  1000 to 2400 
RPM  above 380  C  0.1 to 1.8 s  B1-S2 OK  
Notes  
  
  
If the specified value is not reached, replace oxygen sensor 1 
before catalytic converter (bank 1)  
Note for display field 2:  
Calculated value from engine speed and engine load. 
Note for display fields 3 and 4:  
Period duration is the time between two oxygen sensor voltage jumps (e.g. rich - lean - rich) and is therefore a measurement 
of the aging condition of the oxygen sensor. If the specified time is exceeded, display field 4 will indicate = B1-S1 not OK. 
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        Page 24 of 63

24-96
      
-  Press buttons -0-, -3- and -5- to select "display 
group number 035" and press -Q- button to 
confirm input. System in Basic Setting 35  
1 
2 
3 
4
    
When indicated on display:  
Note:  
The test in display group 035 is activated simultaneously with the test in 
display group 034 Therefore the test result is indicated immediately after 
display group 035 is selected.  -  Check specified value in display field 4.
  
Display fields  
  
1   2   3   4  
Display group 035: Oxygen sensor aging diagnostic, oxygen sensor before catalytic converter (bank 2)  
Display  xxxx/min  
xxx C  
x.x s  
---  
Indicated  Engine speed 
(RPM)  Exhaust 
temperature  Period duration  
Oxygen sensor before  
Catalytic converter  Diagnostic condition  
Functional 
range  630 to 6800  
70 to 850 C  
0 to 3.0 s  
B1-S2 OK  
B1-S2 not OK  
Specified 
value  1000 to 2400 
RPM  above 380  C  0.1 to 1.8 s  B1-S2 OK  
Notes  
  
  
If the specified value is not reached, replace oxygen sensor 2 
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        Page 25 of 63
before catalytic converter (bank 1)  
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