AUDI A4 1995 B5 / 1.G ATQ Engine Ignition System Checking Service Manual
Manufacturer: AUDI, Model Year: 1995, Model line: A4, Model: AUDI A4 1995 B5 / 1.GPages: 65, PDF Size: 0.53 MB
Page 41 of 65

28-36
 
  
Display fields  
  
1   2   3   4  
Display group 021: Ignition -knock control in driving operation  
Display  
xx.x  KW  
xx.x  KW  
  
  
Indicated  
Ignition angle retardation cylinder 5 via 
knock control 
Knock sensor control  Ignition angle retardation cylinder 6 via 
knock control 
Knock sensor control    
  
Specified 
value  0 to 12  KW  
0 to 12  KW  
  
  
Notes  Evaluation  Page 28
-40
   
  
  
Note:  
The number values indicated in display fields 1 and 2 represent actual ignition angle retardation via knock control of the 
individual cylinders. Ignition angle retardation occurs in  KW (crankshaft degrees) toward retardation.      
- Press -C- button.Read Measurin
g Value Block 
Q
Input displa
y group number XXX
    
When indicated on display:  
-  Press buttons -0-, -2- and -2- to select "display group number 022" and press -Q-
button to confirm input. 
Read Measuring Value Block 22  
1 
2 
3 
4
    
When indicated on display:  
-  Check indications in display field 3 and 4.
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Page 42 of 65

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Display fields  
  
1   2   3   4  
Display group 022: Ignition -knock control in driving operation  
Display   xxxx/min   xxx.x %  
xx.x  KW  
xx.x  KW  
Indicated  Engine speed 
(RPM)  Engine 
load  Ignition angle retardation cylinder 1 
via knock control 
Knock sensor control  Ignition angle retardation cylinder 2 
via knock control 
Knock sensor control  
Specified 
value  xxxx/min   12 to 100 
%  0 to 12  KW  
0 to 12  KW  
Notes        Evaluation  Page 28
-40
   
Note:  
The number values indicated in display fields 3 and 4 represent actual ignition angle retardation via knock control of cylinders 
1 and 2. Ignition angle retardation occurs in  KW (crankshaft degrees) toward retardation.      
- Press -C- button.Read Measurin
g Value Block 
Q
Input displa
y group number XXX
    
When indicated on display:  
-  Press buttons -0-, -2- and -3- to select "display group number 023" and press -Q-
button to confirm input. 
Read Measuring Value Block 23  
1 
2 
3 
4
    
When indicated on display:  
-  Check indications in display field 3 and 4.
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Page 43 of 65

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Display fields  
  
1   2   3   4  
Display group 023: Ignition -knock control in driving operation  
Display   xxxx/min   xxx.x %  
xx.x  KW  
xx.x  KW  
Indicated  Engine speed 
(RPM)  Engine 
load  Ignition angle retardation cylinder 3 
via knock control 
Knock sensor control  Ignition angle retardation cylinder 4 
via knock control 
Knock sensor control  
Specified 
value  xxxx/min   12 to 100 
%  0 to 12  KW  
0 to 12  KW  
Notes        Evaluation  Page 28
-40
   
Note:  
The number values indicated in display fields 3 and 4 represent actual ignition angle retardation via knock control of cylinders 
3 and 4. Ignition angle retardation occurs in  KW (crankshaft degrees) toward retardation.      
- Press -C- button.Read Measurin
g Value Block 
Q
Input displa
y group number XXX
    
When indicated on display:  
-  Press buttons -0-, -2- and -4- to select "display group number 024" and press -Q-
button to confirm input. 
Read Measuring Value Block 24  
1 
2 
3 
4
    
When indicated on display:  
-  Check indications in display field 3 and 4.
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Page 44 of 65

28-39
 
  
Display fields  
  
1   2   3   4  
Display group 024: Ignition -knock control in driving operation  
Display   xxxx/min   xxx.x %  
xx.x  KW  
xx.x  KW  
Indicated  Engine speed 
(RPM)  Engine 
load  Ignition angle retardation cylinder 5 
via knock control 
Knock sensor control  Ignition angle retardation cylinder 6 
via knock control 
Knock sensor control  
Specified 
value  xxxx/min   12 to 100 
%  0 to 12  KW  
0 to 12  KW  
Notes        Evaluation  Page 28
-40
   
Note:  
The number values indicated in display fields 3 and 4 represent actual ignition angle retardation via knock control of cylinders 
5 and 6. Ignition angle retardation occurs in  KW (crankshaft degrees) toward retardation. 
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 Evaluation display groups 020/021/022/023/024 - ignition angle retardation  
Indicated on display  
Possible cause  
Corrective action  
All cylinders more than 12  KW  
Knock sensor faulty- Check knock sensor   Page 28
-41
  
Harness connector corroded  
  Knock sensor incorrect 
tightening torque - Loosen knock sensors and tighten to 20 
Nm 
  Engine accessories loose- Secure engine accessories
  Poor fuel quality- Change fuel quality  
(see operating instructions)
One cylinder deviates significantly from 
the others  Harness connector corroded- Check knock sensor   Page 28
-41
  
Engine damage
 Repair Manual, Engine Mechanical, 
Repair Group 15  - Check compression pressure:
  
Engine accessories loose- Secure engine accessories
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Page 46 of 65

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Knock sensors, checking
 
Special Tools and Equipment  
 
VAG1526A
 VAG1594A
 VAG1598/31
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       Component location   Overview of Component 
Locations, page   Page 24
-5   
     
Notes:  
     
Knock Sensor (KS) 1 -G61- and Knock Sensor 
(KS) 2 -G66- themselves cannot be electrically 
tested. 
     Use only gold-plated terminals when servicing 
harness connector for knock sensors. 
     For the knock sensors to function properly, it is 
important that tightening torque be exactly 20 
Nm. 
     Check harness connector from knock sensor to 
wiring harness for corrosion. 
     
Check knock sensors  
    
Note:  
Coolant reservoir screws must be removed and coolant reservoir must be 
placed to side in order to access harness connector for knock sensor for 
bank 2. The coolant hoses can remain connected.  -  Disconnect the harness connector of the relevant knock sensor in 
engine compartment. 
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Check wires from knock sensors to Engine Control Module (ECM).   -  Check all three terminals at knock sensor connector for short circuit to 
each other (terminal 1+2, 1+3, 2+3). 
 
Specification:   (no continuity) - the wires must not have any 
connection to each other. 
-  If there is no connection , replace knock sensor.
-  If no short circuit is detected, check knock sensor wires:
-  Connect VAG1598/31 test box at wiring harness to ECM, do not 
connect ECM   Page 24
-17
 . 
-  Check the following wire connections for open circuit and short circuit 
to Ground (GND) and B+: 
    
Knock Sensor (KS) 1 -G61- Harness connector  
Terminal  
VAG1598/31 test box  
Socket  
1 (signal)   106  
2 (Ground -GND-)   99  
3 (shielding)   108  
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Page 49 of 65

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Knock Sensor (KS) 2 -G66- Harness connector  
Terminal  
VAG1598/31 test box  
Socket  
1 (signal)   107  
2 (Ground -GND-)   99  
3 (shielding)   108  
-  Repair open circuit or short circuit if necessary.
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Page 50 of 65

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Camshaft Position (CMP) sensor, 
checking
 
Special Tools and Equipment  
 
VAG1526A
 VAG1527B
 VAG1594A
 VAG1598/31
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