Page 12 of 59
28-11
 
    
-  Disconnect 4-pin harness connector -1- at ignition coil -2-.
    
If specified values are not obtained:  -  Connect VAG1527B voltage tester to connector terminals 2 and 3.
-  Operate starter briefly. 
 
LED must blink (brief blink signal).
-  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 59
28-12
 
    
If no malfunctions are found in wires:  -  Check following wire connections for open circuit and short circuit to 
Ground (GND) and B+: Harness connector  
Terminal  
VAG1598/31 test box  
Socket  
3 (Cyl. 1)   102  
3 (Cyl. 2)   95  
3 (Cyl. 3)   103  
3 (Cyl. 4)   94  
-  Repair open circuit or short circuit if necessary.
-  Replace combined component, ignition coil with power output stage.
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        Page 15 of 59
28-14
      
Note:  
     The motronic Engine Control Module (ECM) 
power supply relay -J271- supplies voltage to the 
ignition coils with power output stages and the 
Engine Control Module (ECM) at pin 121. 
     
Test requirement: 
     
Fuses for engine electronics OK 
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations   
     
Test sequence  
    
-  Remove engine cover (arrows).
    
-  Disconnect 4-pin harness connector -1- at one of ignition coils -2-.
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        Page 16 of 59
28-15
 
    
If specified value is not obtained:  -  Connect multimeter for voltage measurement as follows.Harness connector  
Terminal  
Measure to  
1   Engine Ground (GND)  
-  Switch ignition on.
 
Specification: approx. battery voltage
-  Switch ignition off.
    
-  Pull off rubber seal of plenum chamber cover in direction of arrow.
-  Remove cover -1- toward front.
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        Page 18 of 59
28-17
 
    
If wire connection is OK:  -  Check following connection for open circuit according to wiring 
diagram: 3-socket relay carrier in E-box, plenum 
chamber, position 2  
Terminal  
Harness connector at 
ignition coils  
  
Terminal  
6   1  
-  Repair open circuit if necessary.
-  Check voltage supply of motronic Engine Control Module (ECM) power 
supply relay -J271-   Page 28
-18
 . 
-  Check activation of motronic Engine Control Module (ECM) power 
supply relay -J271-   Page 28
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        Page 20 of 59
28-19
      
Checking activation  
    
If specified value is not obtained:  -  Connect multimeter for voltage measurement as follows.3-socket relay carrier in E-box, plenum chamber, 
position 2  
Terminal  
Measure 
to  
  
4   B+  
-  Switch ignition on.
 
Specification: approx. battery voltage
-  Switch ignition off.
-  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 38 of 59
28-37
      
Test requirements: 
     
Fuses for engine electronics OK 
     
       Electrical Wiring Diagrams, Troubleshooting & 
Component Locations   
     
Battery voltage at least 12.7 V 
     Generator OK 
     
Test sequence  
     
-  Connect VAG1598/31 test box at wiring harness 
to Engine Control Module (ECM), do not connect 
ECM  Page 24
-19
 . 
     
-  Switch ignition on.
     
Note:  
     
The plus voltage supply for the Engine Control 
Module (ECM) travels via terminal 3 and 121 
(terminal 15) as well as terminal 62 (terminal 
30). 
     
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        Page 40 of 59
28-38
      
-  Connect multimeter for voltage measurement as 
follows: 
     
VAG1598/31 test box  
Socket  
Measure to  
1   B+  
2   B+  
62   Engine Ground (GND)  
     
 
Specification: approx. battery voltage
     
-  Connect multimeter for voltage measurement as 
follows: 
     
VAG1598/31 test box  
Socket  
Measure to  
3   Engine Ground (GND)  
     
-  Switch ignition on.
     
 
Specification: approx. battery voltage
      If specified values are not obtained:  
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