light AUDI A8 1999 D2 / 1.G ATQ Engine Motronic On Board Diagnostic Workshop Manual

01-2

If the ECM recognizes malfunctions that lead to
a degradation of emissions values, it indicates
them by lighting the Malfunction Indicator Lamp
(exhaust warning lamp -K83-). Clarification of
this lamp Page 01
-3 .

"E-Gas"-relevant malfunctions are also
indicated in the instrument cluster by the
warning lamp for Electronic Power Control
("EPC warning lamp").
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01-3

Malfunction Indicator Lamp (MIL),
significance

If the ECM recognizes malfunctions that lead to a
degradation of emissions values, it indicates
them by lighting the Malfunction Indicator Lamp
for exhaust.

Installation position of exhaust MIL
Note:
The Malfunction Indicator Lamp (MIL) can blink or remain lit continuously.
DTC memory should be checked in both cases Page 01
-15
.
Blinking: There is a malfunction that causes damage to the catalytic
converter in this driving condition (e.g. combustion misfire). In this
case, vehicle must only be driven at reduced power! Continuously lit: There is a malfunction that causes increased
emissions. Check DTC memory for Motronic ECM and automatic
transmission (if installed). If there are driveability problems or if there is a customer complaint
and the exhaust MIL is not lit, DTC memory must be checked. There
may be DTCs stored that do not cause the exhaust MIL to light up
immediately, but only if malfunction is recognized again after repeated
engine starts.
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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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01-11

- Press -Print- button to turn on Scan Tool (ST)
printer. Indicator lamp in button must light up.

- Press button 1 to select "Rapid data transfer"
operating mode 1. Rapid data transfer
HELP
Insert address word XX

When indicated on display:
Note:
The address word 00 initiates the automatic test sequence, i.e. it results in
a DTC check on all OBD capable systems in the vehicle via rapid data
transfer.
- Press buttons -0- and -1- to select "engine electronics" and press -Q-
button to confirm input.
3B0907551BA
2.8l V6/5V
G
0003
Codin
g 07251
WSC 12345

VAG1551 Scan Tool (ST) display indicates control module identification,
e.g.:
Note:
Control module identification can be printed by pressing the PRINT key of
the VAG1551 scan tool.
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