AUDI A6 1997 C5 / 2.G ATW Engine Ignition System User Guide

28-10

- 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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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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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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28-13


Motronic Engine Control Module (ECM)
power supply relay -J271-, checking

Special tools and equipment

VAG1526A
VAG1594A
VAG1598/31
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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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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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28-16


- Remove Heater Core E-box cover (arrows).

- Disconnect voltage supply relay -3-.
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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
-19
.
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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.
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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
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