Page 4 of 63
24-79
      
Notes:  
     
For the defined troubleshooting procedure, it is 
possible, to switch oxygen sensor control off by 
selecting display group 099 under "basic 
setting" and switch it on again under "read 
measuring value block". 
     After selecting display group 099 (either in 
"basic setting" or "read measuring value 
block"), it is possible to switch back and forth 
between "basic setting" (function 04) and "read 
measuring value block" (function 08) by 
pressing buttons 4 or 8 on the VAG1551. 
     Once function 04 "basic setting" is exited, 
oxygen sensor control is automatically switched 
on again. 
     
Test requirements:  
     Road test performed and DTC memory 
erased. 
     Coolant temperature at least 80  C   
Display group 4, display field 3 
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        Page 5 of 63
24-80
      
Function test  
     
-  Connect VAS5051 tester or VAG1551 scan tool 
and select the control module for engine 
electronics using "address word" 01   Page 01
-
9 . 
     
   Engine must run at idle for this.Rapid data transfer  
HELP
Select function XX
    
When indicated on display:  
Note:  
During basic setting, the Evaporative Emission (EVAP) canister purge 
regulator valve (EVAP valve -N80-) is closed and the A/C compressor is 
switched off  -  Press buttons -0- and -4- to select "Initiate basic setting" and press -Q- 
button to confirm input. 
Basic Settin
g 
Q
Input displa
y group number XXX
    
When indicated on display:  
-  Press buttons -0-, -3- and -0- to select "display group number 030" and 
press -Q- button to confirm input. 
System in Basic Setting 30  
1 
2 
3 
4
    
When indicated on display:  
Note:   -  Check oxygen sensor status in display fields 1 and 3.
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        Page 7 of 63
24-81
 
  
Display fields  
  
1   2   3   4  
Display group 030: Oxygen sensor status with engine at idle  
Display  
X X X   X X X  
X X X   X X X  
Indicated  
Oxygen sensor status, 
bank 1, sensor 1  Oxygen sensor status, 
bank 2, sensor 1  Oxygen sensor status, 
bank 2, sensor 1  Oxygen sensor status, 
bank 2, sensor 2  
Functional 
range  0 = off  
1 = on  0 = off  
1 = on  0 = off  
1 = on  0 = off  
1 = on  
Specified 
value  1 1 1  1 1 0  
1 1 1   1 1 0  
Notes  
Meaning of display   Page 01
-90
   
If specified value is not obtained   Page 24
-89
   
If specified value is obtained but there is a malfunction stored in DTC memory  Check oxygen 
sensor adaptation values and control, page   Page 24
-83
   
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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 9 of 63
24-83
      
Checking oxygen sensor adaptation values 
and control  
     
- Press -C- button.Basic Setting 
Q
Input displa
y group number XXX
    
When indicated on display:  
-  Press buttons -0-, -3- and -3- to select "display group number 033" and 
press -Q- button to confirm input. 
System in Basic Setting 33  
1 
2 
3 
4
    
When indicated on display:  
-  Check oxygen sensor control in display fields 1 and 3.
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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 11 of 63
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 Evaluation display group 033  Display field: 1 / 3  
Possible cause  
Corrective action  
Values in range: 
-10.0 to -25.0 %   
Oxygen sensor heating faulty- Check oxygen sensor heating   Page 
24
-116
 
or  
Values in range:   
Open circuit in wires between oxygen sensor 
and control module - Check primary voltage   Page 24
-89
10.0 to 25.0 %  
or  
Value does not fluctuate 
by at least 2 %   
Short circuit to Ground (GND) or B+ between 
oxygen sensor and control module - Check oxygen sensor wires bank 1   
Page 24
-90
 
- Check oxygen sensor wires bank 2   
Page 24
-91
 
  
 
False air in intake area- Check intake system for leaks and 
repair false air   Page 24
-64
 
  
 
Fuel pressure too low or too high- Check fuel pressure regulator   Page 
24
-30
 
  
 
Fuel return line is kinked or clogged- Check fuel return line.
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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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