light AUDI A3 1998 8L / 1.G ATW Engine On Board Diagnostic Workshop Manual

01-2

If the ECM recognizes malfunctions that lead to
a worsening of emissions values, it indicates
them by lighting the Malfunction Indicator Lamp
(MIL) -K83- in the instrument cluster. Meaning
of Malfunction Indicator Lamp (MIL) -K83-
Page 01
-3 .

"E-Gas"-relevant malfunctions are also
indicated 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
worsening of emissions values, it indicates them
by lighting the Malfunction Indicator Lamp (MIL).

Installation location of Malfunction Indicator Lamp (MIL)
The Engine Control Module (ECM) switches on the Malfunction Indicator
Lamp (MIL) after ignition is switched on. Shortly after engine is started,
the exhaust MIL will go out. This requires, first of all, that the Engine
Control Module (ECM) does not detect a malfunction that worsens the
emissions values and, secondly, that activation of the lamp by the Engine
Control Module (ECM) is OK.
If malfunctions that worsen emissions are recognized during operation of
the engine, the ECM switches on the exhaust MIL in instrument cluster.
(These malfunctions are listed in the DTC table). An entry is made in DTC
memory at the same time.
The Malfunction Indicator Lamp (MIL) can blink or remain lit continuously.
DTC memory should be checked in either case Page 01
-16
.
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01-4

Continuously lit:
There is a malfunction that causes increased
emissions. Check DTC memory for Motronic
ECM and automatic transmission (if installed).
Check DTC memory if there is a driveability
problem or a customer complaint, but the
Malfunction Indicator Lamp (MIL) is not lit. There
may be DTCs stored that do not cause the
exhaust MIL to light up immediately, but only
after engine is started again and malfunction is
recognized again.

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!

Note:
Catalytic converter must be checked after
malfunction is repaired.
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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
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01-12
Depending on desired function Table
"Selectable functions", Page 01
-15
:

- Switch ignition on.
or

- Start engine.

- 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
Enter 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.
4B0906018Q
1.8 L R4/5VT
G 0008
Codin
g 07551
WSC 12345

VAG1551 Scan Tool (ST) display indicates control module identification,
e.g.
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