Page 8 of 59
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If LED does not light up:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
If LED lights up:
Checking voltage supply
Test requirement:
Electrical Wiring Diagrams, Troubleshooting & Component Locations - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
2 B+
4 B+
LED must light up.
- Check wire connections.
- Check voltage supply
Fuses for engine electronics OK
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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 38 of 59
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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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