wiring AUDI A6 1999 C5 / 2.G ATQ Engine Motronic On Board Diagnostic Workshop Manual

01-5

Function test of warning lamp

- Switch ignition on.


Warning lamp for On Board Diagnostic
(Malfunction Indicator Lamp -MIL-) must
light up

A - Warning lamp for On Board Diagnostic
(Malfunction Indicator Lamp -MIL-) does not
light up

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

- 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:

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01-6

- Check the 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 binder

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

- Replace Engine Control Module (ECM) Page
24
-21
.
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01-7

B - Warning lamp for On Board Diagnostic
(Malfunction Indicator Lamp -MIL-) remains lit
constantly

- Check DTC memory of Engine Control Module
(ECM) Page 01
-15
.
If no DTCs are stored:

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

- Remove instrument cluster:

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


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

Test box
VAG1598/31
Socket
Instrument cluster

Terminal
47 Electrical Wiring Diagrams,
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01-9

VAS 5051 vehicle diagnostic, testing
and information system orVAG1551
Scan Tool (ST), connecting and
selecting functions


Test requirements:

Fuses for engine electronics OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder

Fuel Pump (FP) OK, checking Page 24
-
49
.

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

Procedure

Note: - Connect VAS5051 tester to vehicle with VAS5051/1 diagnostic wire.
Alternately, VAG1551 Scan Tool (ST) can also be attached using
VAG1551/3B cable.
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01-10

WARNING!

Observe safety precautions Page 01
-8 .

Note:
The following description only explains
implementation of On Board Diagnostic using
VAG1551 Scan tool.
When using the VAS5051 tester, observe the
tester's instructions for use V.A.G - ON BOARD DIAGNOSTIC
HELP
1 - Rapid data transfer 1)2 - Blink code output 1
)

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
binder
Depending on desired function Table "Selectable functions", page
Page 01
-14
:
- Switch ignition on.
or
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01-13

Notes:

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 does not answer

When indicated on display:
Rapid data transfer
HELP
K-wire not switchin
g to Ground

- Perform troubleshooting procedure after "troubleshooting procedure leak
test":
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder
Rapid data transfer
HELP
K-wire not switchin
g to B+

Rapid data transfer
HELP
Error in communication link

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)
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