1996 AUDI TT ignition

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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28-14

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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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.
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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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28-19

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
-19
.
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28-37

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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28-38

- Connect multimeter for voltage measurement as
follows:

VAG1598/31 test box
Socket
Measure to
1 B+
2 B+
62 Engine Ground (GND)


Specification: approx. battery voltage

- Connect multimeter for voltage measurement as
follows:

VAG1598/31 test box
Socket
Measure to
3 Engine Ground (GND)

- Switch ignition on.


Specification: approx. battery voltage
If specified values are not obtained:
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