wiring AUDI TT 1995 8N / 1.G ATW Engine On Board Diagnostic Workshop Manual

01-6

Function test of warning lamp

- Switch ignition on.


Exhaust MIL must light up

A- Exhaust MIL does not light up

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

- Bridge sockets 1 and 47 of test box.

- Switch ignition on.


Warning lamp must light up.
If warning lamp does not light up:

- Switch ignition off.

- Remove instrument cluster:

Repair Manual, Electrical Equipment, Repair
Group 90; Instrument cluster, removing and
Pa
ge 6 of 19 On Board Dia
gnostic
(OBD
)
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.01.1

01-7

- Check following wire connection for open circuit
and short circuit to B+:

Test box
VAG1598/31
Socket
Instrument cluster

Terminal
47 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations

- Repair open circuit or short circuit if
necessary.
If wire connection is OK:

- Replace Engine Control Module (ECM) Page
24
-23

Pa
ge 8 of 19 On Board Dia
gnostic
(OBD
)
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.01.1

01-8

B- Exhaust MIL remains constantly lit

- Check DTC memory of Engine Control Module
(ECM) Page 01
-16
.
If no DTCs are stored:

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

- Remove instrument cluster:

Repair Manual, Electrical Equipment, Repair
Group 90; Instrument cluster, removing and installing


- Check following wire connection for short circuit
to Ground (GND):

Test box
VAG1598/31
Socket
Instrument cluster

Terminal
47 Electrical Wiring Diagrams,
Troubleshooting & Component
Pa
ge 9 of 19 On Board Dia
gnostic
(OBD
)
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.01.1

01-10

VAS5051 tester or VAG1551 scan tool,
connecting and selecting functions


Test requirements:

Fuses for engine electronics OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations

Fuel Pump (FP) relay OK; checking Page 24
-53
.

Battery voltage at least 12.7 V
Ground (GND) connections at engine and
transmission OK

Procedure

Note:
Data Link Connector (DLC) is located in front left knee bolster. - Connect VAS5051 tester to vehicle with VAS5051/1 diagnostic wire.
Alternately, VAG1551 Scan Tool (ST) can also be attached using
VAG1551/3A adapter.
Pa
ge 12 of 19 On Board Dia
gnostic
(OBD
)
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.01.1

01-11

WARNING!

Observe safety precautions Page 01
-9 .

Note:
The following description only explains
implementation of On Board Diagnostic using
VAG1551 Scan tool. When using the VAS5051
tester, observe instructions in the tester's user
manual. VAG - On Board Diagnostic (OBD)
HELP
1- Rapid data transfer1
)
2- Blink code output1
)

Indicated on display 1) Operating modes 1 and 2 are displayed alternately
Note:
If nothing appears in display:
- Perform troubleshooting procedure after "troubleshooting procedure leak
test":
Electrical Wiring Diagrams, Troubleshooting & Component Locations
Pa
ge 13 of 19 On Board Dia
gnostic
(OBD
)
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.01.1

01-14

Note:

It will be possible to display the control module
identification again after pressing buttons -0-
and -1- to select "Check Control Module
Versions" and confirming with the -Q- button.
Rapid data transfer
HELP
Control module not respondin
g!

- Perform troubleshooting procedure after "troubleshooting procedure leak
test":
Electrical Wiring Diagrams, Troubleshooting & Component Locations
When indicated on display
Rapid data transfer
HELP
K-wire does not switch to Ground

Rapid data transfer
HELP
K-wire does not switch to B+

Rapid data transfer
HELP
Malfunction in communication set-up

Pa
ge 17 of 19 On Board Dia
gnostic
(OBD
)
11/21/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU06.01.1