ground AUDI A3 2000 8L / 1.G ATW Engine Ignition System Workshop Manual

28-6
If malfunction follows the spark plug:

- Replace spark plug.
If malfunction remains at original cylinder:

- Switch ignition coil from faulty cylinder with one
from another cylinder.
If malfunction follows the ignition coil:

- Replace ignition coil.

Check Ground (GND) connection

- Disconnect 4-pin harness connector -1- at ignition coil -2-.
Pa
ge 7 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1

28-8


If specified value is obtained:
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
- Check activation of power output stages Page 28
-10
.

- Pull off rubber seal of plenum chamber cover in direction of arrow.
- Remove cover -1- toward front.
Pa
ge 9 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1

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.
Pa
ge 13 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1

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.
Pa
ge 16 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1

28-18

Checking voltage supply

If specified value is not obtained:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
If no malfunctions are found in wires: - Connect multimeter for voltage measurement as follows.3-socket relay carrier in E-box, plenum
chamber, position 2
Terminal
Measure to

2 Engine Ground
(GND)
9 Engine Ground
(GND)

Specification: approx. battery voltage
- Check wire connection between central electronics and voltage supply
relay for open circuit.
- Replace central electrics.
Pa
ge 19 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1

28-20


If no malfunctions are detected: - Check following wire connection for open circuit and short circuit to
Ground (GND) and B+: Relay carrier below left cover, at bulkhead
Terminal
VAG1598/31 test box
Socket
4 21
- Repair open circuit or short circuit if necessary.
- Replace motronic Engine Control Module (ECM) power supply relay -
J271-.
Pa
ge 21 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1

28-24

Checking wire connections

- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

- Disconnect connector -1- at Intake Air Temperature (IAT) sensor -G42-
(item no. 2).

- Check following wire connections for open circuit and short circuit to
Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
1 85
2 108
- Check both wires to each other for short circuit.
- Repair open circuit or short circuit if necessary.
Pa
ge 25 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1

28-29
If specified value is obtained:

- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

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
1 (signal) 82
2 (Ground -GND-) 90
3 (shielding) 108
- Repair open circuit or short circuit if necessary.
- Replace Engine Control Module (ECM) Page 24
-23
Pa
ge 30 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1

28-34
If specified value is obtained:

- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.

Coolant temperature sensor with square
connector:

Coolant temperature sensor with oval connector: - Check following wire connections for open circuit and short circuit to
Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
1 (signal) 93
3 108

- Check following wire connections for open circuit and short circuit to
Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
3 108
4 (signal) 93
Pa
ge 35 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1

Ground (GND) supply of the Engine Control
Module (ECM) travels via connector terminal 1
and terminal 2.
Pa
ge 39 of 59 I
gnition s
ystem, checkin
g
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.28.1