check engine AUDI A4 1997 B5 / 1.G AWM Engine Oxygen Sensor Control Checking Workshop Manual
[x] Cancel search | Manufacturer: AUDI, Model Year: 1997, Model line: A4, Model: AUDI A4 1997 B5 / 1.GPages: 46, PDF Size: 0.3 MB
Page 2 of 46

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Test requirements:  
     
Exhaust system free of leaks. 
     Coolant Temperature at least 80  C. 
     
Test sequence  
     
- Connect VAS5051 tester   Page 01
-7 and 
select vehicle system "01 - Engine electronics". 
Engine must run at idle for this. 
    
Display on VAS5051:  
-  In selection -1-, click on the diagnostic function "04 - Basic setting".
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Page 3 of 46

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Display on VAS5051:  
1 - Enter display group Max. input value = 255
-  Select function "030" in button field -2- for "display group number 030" 
and press Q button to confirm input. 
    
Display on VAS5051:  
Notes:  -  Check specified value in display field -1-.
Increase engine speed to obtain specified values faster. "Oxygen sensor status" indicates status of oxygen sensor control and 
oxygen sensors. 
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Page 6 of 46

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- 
Press   button to change into display group 
033.      
-  Check oxygen sensor control in display fields -1-
and -2-. 
  
Display fields  
  
1   2   3   4  
Display group 033: Oxygen sensor control  
Display  
xx.x %  
x.xxx V  
  
  
Indicated  
Oxygen sensor control bank 1, sensor 1  
Oxygen sensor voltage, Bank 1, sensor 1  
    
Specified 
value  Value must fluctuate at least 2 % in the 
range -10.0 to 10.0 %  0.130 to 3.600 volts  
  
  
Note  
If specified value is not obtained   
Continuation,  Page 24
-77
   
If specified value is not obtained   Evaluation 
display group 033,   Page 24
-80
   
  
  
Note for display field 2:  
The oxygen sensor voltage signal which is processed and calendered by the Engine Control Module (ECM) will be displayed. 
1.5 volts in display corresponds to Lambda 1. 
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Page 12 of 46

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       If specified value is not obtained:  
     
-  Check oxygen sensor wiring.
      If specified value is obtained:  
     
-  Replace Heated Oxygen Sensor (HO2S)-G39-
. 
     
Checking oxygen sensor wires  
    
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. 
-  Connect VAG1598/31 test box at wiring harness to Engine Control 
Module (ECM), do not connect ECM   Page 24
-19
 . 
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Page 13 of 46

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 Electrical Wiring Diagrams, Troubleshooting & Component Locations   
If wire connection is OK:  -  Check the following wire connections for open circuit.Harness connector  
Terminal  
VAG1598/31 test box  
Socket  
1   70  
2   71  
5   51  
6   52  
-  Repair open circuit if necessary.-  Check wires to each other for short circuit.
-  Replace Engine Control Module (ECM)   Page 24
-22
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Page 15 of 46

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Test sequence  
     
- Connect VAS5051 tester   Page 01
-7 and 
select vehicle system "01 - Engine electronics". 
Engine must run at idle for this. 
    
Display on VAS5051:  
-  In selection -1-, click on the diagnostic function "04 - Basic setting".
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Page 16 of 46

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Display on VAS5051:  
1 - Enter display group Max. input value = 255
-  Select function "034" in button field -2- for "display group number 034" 
and press Q button to confirm input. 
-  Use VAG1788/10 RPM adjuster to adjust engine speed to between 
2300 and 2800 RPM. 
    
Display on VAS5051:  
Note:  
This process can take a few minutes.  -  Check specified value in display field -4-.
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Page 17 of 46

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Display fields  
  
1   2   3   4  
Display group 034: Diagnostic oxygen sensor aging  
Display  xxxx/min  
xxx C  
x.x  
---  
Indicated  Engine speed 
(RPM)  Exhaust 
temperature  Dynamic factor  Diagnostic condition  
Functional 
range       
  
Test OFF  
Test ON  
B1-S2 OK  
B1-S2 not OK  
Specified value   2300 to 2800 RPM  
larger than 350  C  
0.5 to 2.5   B1-S2 OK  
Note  
  
  
If specified value is not obtained   Continuation,   Page 
24
-88
   
Note for display field 2:  
Calculated value from engine speed and engine load. 
Note for display fields 3 and 4:  
The dynamic factor is a characteristic for oxygen sensor aging. The smaller the dynamic factor, the further the oxygen sensor 
aging process has advanced. 
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       If specified value is obtained:  
     
-  Check voltage supply of oxygen sensor 
heating. 
     
Checking voltage supply for oxygen sensor 
heating  
    
Note:  
When the Engine Control Module (ECM) switches oxygen sensor heating 
on and off, it may be observed via the function "read measuring value 
block", in display group number 041 display field 2. 
If there is no voltage:  -  Connect multimeter between terminal 3 and 4 for voltage 
measurement. 
- Start engine.
 
Specification: approx. battery voltage
    
-  Connect multimeter for voltage measurement as follows.Harness connector  
Terminal  
Measure to  
3 (B+)   Vehicle Ground (GND)  
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Page 23 of 46

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-  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
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