wiring AUDI A8 1998 D2 / 1.G ATQ Engine Ignition System Checking Workshop Manual
[x] Cancel search | Manufacturer: AUDI, Model Year: 1998, Model line: A8, Model: AUDI A8 1998 D2 / 1.GPages: 65, PDF Size: 0.53 MB
Page 2 of 65
28-2
Safety precautions
To reduce the risk of personal injury and/or
damage to the fuel injection and ignition system,
always observe the following:
Do not touch or pull off ignition wires when
engine is running or turning at starting RPM.
Always switch ignition off before disconnecting
or reconnecting wires for the injection and
ignition system, including high voltage wiring
and test leads.
If engine is to be cranked at starting RPM
without starting (e.g. for compression testing),
disconnect connector from ignition coils and
from fuel injectors.
It is possible that the control module will
recognize a malfunction and store a DTC during
some tests. After completing all tests and
repairs, DTC memory should therefore be
checked and erased if necessary. Readiness
code must be generated after DTC memory is
erased Page 01
-82
.
Always switch ignition off before cleaning
engine.
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Page 12 of 65
28-10
Checking Ground (GND) supply of power
output stage
If LED does not light up:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
2 B+
LED must light up.
- Check the wire connection for open circuit:
- Repair open circuit if necessary.
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Page 13 of 65
28-11
Checking voltage supply to ignition coils
Note:
Voltage is supplied to ignition coils via Fuel
Pump (FP) relay.
Test requirement:
Fuse for ignition coils OK
Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
If LED does not light up: - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
1 Engine Ground (GND)
- Operate starter.
LED must light up.
- Check the wire connection for open circuit:
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Page 14 of 65
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Repair open circuit if necessary.
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Page 15 of 65
28-12
Checking activation
- Disconnect connectors from all six fuel injectors.
(afterward check DTC memory)
If specified values are not obtained: - Connect VAG1527B voltage tester as follows:Harness connector
Terminal
Measure to
3 Engine Ground (GND)
4 Engine Ground (GND)
5 Engine Ground (GND)
- Operate starter for a few seconds.
LED must blink (brief blink signal).
- Switch ignition off.
- Connect VAG1598/31 test box at wiring harness to ECM, do not
connect ECM Page 24
-17
.
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Page 20 of 65
28-17
Checking wire connections
- 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+: 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.
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Page 24 of 65
28-21
If specified value is not obtained:
- Replace engine speed (RPM) sensor.
If specified value is obtained:
If specified value is not obtained:
If specified value is obtained: - Connect multimeter to terminals 2 and 1 (shielding) and to terminals 3
and 1 (shielding) for resistance measurement.
Specification: each (no continuity)
- Replace engine speed (RPM) sensor.
- Connect VAG1598/31 test box at wiring harness to ECM, do not
connect ECM Page 24
-17
.
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Page 30 of 65
28-27
All models
Range A shows the resistance values for the
temperature range from 0-50 C, and range B
shows the values for the temperature range from
50-100 C.
Read-out examples:
If specified value is not obtained:
If specified value is obtained:
30 C corresponds to a resistance of 1500 to 2000 80 C corresponds to a resistance of 275 to 375
- Replace coolant temperature sensor.
- Connect VAG1598/31 test box at wiring harness to ECM, do not
connect ECM Page 24
-17
.
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Page 34 of 65
28-31
Test requirements:
Fuse for Engine Control Module (ECM) OK
Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
Battery voltage at least 12.7 V
Generator OK
Test sequence
- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.
- Switch ignition on.
Note:
The plus voltage supply for the Engine Control
Module (ECM) travels via connector terminal 3
(terminal 15) and connector terminal 62
(terminal 30).
Ground (GND) supply of the Engine Control
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Page 37 of 65
- Check wire connections.
Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
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