power AUDI A4 1999 B5 / 1.G ATW Engine Ignition System Workshop Manual

28-3
Technical data

Engine identification
ATW (1.8 L / 5V/ 110 kW engine)
Idle speed
Engine speed cannot be adjusted, it is
regulated by idle stabilization Front Wheel Drive (FWD): 740 to 860 RPM
All-Wheel Drive Vehicles: 800 to 920 RPM
Engine speed (RPM) limitation
Via fuel injector shut-off
about 6800 RPM
Ignition timing is determined in the control
module
It is not possible to adjust the ignition
timing
Ignition system Single coil ignition system with 4 ignition coils (power output stages integrated)
that are connected directly to spark plugs via the ignition cables.
Spark plugs Tightening torque 30 Nm.
Firing sequence 1-3-4-2
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Ignition coils with power output stages,
checking

Special tools and equipment

VAG1526A
VAG1527B
VAG1594A
VAG1598/31
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Test sequence

Note:
The ignition coil and power output stage are
combined in one complete component.

Recognize a non-functional or misfiring cylinder as follows:
If misfires were recognized:
If no misfires were recognized:
or
If faulty cylinder is recognized: - Remove engine cover (arrows).
- Check misfire recognition Page 28
-51
.
- Continue with test at indicated cylinder "If faulty cylinder is
recognized". - Disconnect connectors from fuel injectors in sequence with engine
running and observe engine operation.
- Compare spark plugs from all cylinders to each other. Check
electrodes for carbon fouling..
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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.
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- Perform following tests marked with dots:

Checking activation of power output stages
Note:
Fuel must not be injected during the test to avoid damaging catalytic
converter. Connectors must therefore be disconnected from fuel injectors.
Check wire connection from 3-socket relay carrier, position 2, terminal
6 to harness connector at ignition coil terminal 1. Check motronic Engine Control Module (ECM) power supply relay -
J271- Page 28
-13
.
- Remove all harness connectors to injectors.
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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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Motronic Engine Control Module (ECM)
power supply relay -J271-, checking

Special tools and equipment

VAG1526A
VAG1594A
VAG1598/31
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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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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
-19
.
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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-.
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