2000 AUDI A4 light

01-2

The Exhaust Malfunction Indicator Light (MIL) in
the instrument cluster will be switched on if the
engine control module recognizes malfunctions
which have an affect (decrease emissions) on
exhaust emissions Page 01
-3 .

Malfunctions relating to the electronic throttle
are also indicated by a Electronic Power
Control (EPC) warning light in the instrument
cluster.
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01-3

Exhaust Malfunction Indicator Light
(MIL), significance

If the Engine Control Module (ECM) recognizes
emission related malfunctions, this is indicates by
the MIL coming on.

Component location of MIL
Note:
When a recognized malfunction switches on the MIL, it will either blink or
light continuously. In either case, the DTC memory must be checked
Page 01
-15
.
If the MIL starts to blink, there is a malfunction that can lead to damage of
the Three Way Catalytic Converter (TWC). In this case driving should be
only continue with reduced power until the MIL goes out or stays on
continuously.
Continuos MIL
If the MIL lights continuously, there is malfunction that affects exhaust
emissions. In this case the DTC memory of the ECM and Transmission
Control Module (TCM) (if equipped) must be checked.
Some malfunctions may occur without causing the MIL to come on. When
driveability or performance problems are reported and there is no
indication from the MIL, the operation of the MIL must be checked. In
addition, the DTC memory of the ECM and TCM must be checked, as
there may be malfunctions stored that do not switch the MIL on
immediately.
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01-4

Checking function

- Switch ignition on.

The MIL must light up
If the MIL does not light with ignition switched:

Cause:
MIL is not
activated or does
not light up
because of an
open circuit. Corrective action:
The MIL should light up.
If the MIL does not light up:
If the lamp and the voltage - Switch ignition off
- Connect VAG1598/31 test
box Page 24
-20

- Bridge sockets 2 and 47 on
test box
- Switch ignition on.
- Switch ignition off.
- Check whether lamp is
burned out and test voltage
supply to lamp wiring
diagram.
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01-8

Mode 5 displays the static dimensions of the oxygen sensors, which are legally required. Since these dimensions are not
directly relevant to oxygen sensor diagnostics, mode 5 is insignificant for the authorized Audi center.
With mode 6 all measured values can be checked from components and systems that are not constantly monitored.
Using mode 7, DTCs can be checked for which the Malfunction Indicator Light (MIL) is not yet lit (MIL is not on, no DTCs
under mode 3).
Under mode 8 the tank leak test will be checked.
With mode 9 the following vehicle information can be read out: Vehicle Identification Number (VIN), Part number and
program/data level of the engine control module and the check sum (this value is a internal calculated value).
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01-11

- If no display appears, check diagnostic
cables:

Electrical Wiring Diagrams, Troubleshooting &
Component Locations Depending on the function required:

- Switch ignition on.

or

Start engine Page 01
-6 , table of available
functions.

- Switch on printer with PRINT button (indicator
light in button lights up).

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

Indicated on display:
Rapid data transfer
Q
01 - En
gine Electronics

- Press buttons -0- and -1- to insert "Engine electronics" address word
01.
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01-15

Diagnostic Trouble Code (DTC) Memory,
checking and erasing


- Connect vehicle diagnostic, testing and
information system VAS5051 or VAG1551 scan
tool and select "Engine Electronics" by entering
address word 01 Page 01
-9. When doing this
the engine must be idling.
Only if engine does not start:

- Check engine with ignition switched on.

- Switch on printer with PRINT button (indicator
light in button lights up). Rapid data transfer
HELP
Select function XX

Indicated on display
- Operate scan tool according to information on display:
- Press buttons -0- and -2- to select function "Check DTC Memory" and
confirm entry with -Q- button.
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01-19
Diagnostic Trouble Code (DTC) table

Notes:

If malfunctions occur in the sensors and components being monitored, they will be stored in the DTC memory together
with an indication of the type of malfunction. Notes on Engine Power Control (EPC) (drive by wire) Page 24
-139
.
Malfunctions relating to the electronic throttle are also indicated by the EPC (Electronic Power Control) warning light in the
instrument cluster.
Malfunction which decrease exhaust emissions are indicated by an Exhaust Malfunction Indicator Light (MIL), the MIL is
located in the instrument cluster. As soon as certain malfunction are recognized, the MIL is switched on immediately.
There are also malfunctions, were the MIL is switched on only after the engine is started again.
Sporadically occurring malfunctions (temporary malfunctions) will be indicated on the VAG1551 display as "SP."
The DTC table is arranged according to the 5-digit DTC in the left-hand column.
If a malfunction is stored in the DTC memory and then does not occur again during the next 40 engine warm-up phases,
the DTC will be automatically erased.
Components that are indicated as being faulty by the VAG1551 should not be replaced immediately. Always start by
checking the wiring, connectors and Ground (GND) connections for the component using the current wiring diagram. This
is particularly important in the case of sporadic malfunctions (indicated by the letters "SP"on the scan tool display).
If the connector for the engine control module is disconnected or if the battery is disconnected, all the learned values
(adaptation values) stored in the control module will be erased, although the contents of the DTC memory will remain
intact. The next time the engine is started the idling may be rough at first. In this case let the engine run at idle for a few
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01-20

DTC
Description of malfunction
Corrective action
SAE
VAG


P0101 16485 Mass Air Flow (MAF) sensor -
G70-
Implausible signal - Check Mass Air Flow (MAF) sensor Page 24
-59
P0102 16486 Mass or Volume Air Flow
Circuit
Low input
2) - Check Mass Air Flow (MAF) sensor -G70 Page 24
-59
P0103 16487 Mass or Volume Air Flow
Circuit
High Input
2)

P0106 16490 Manifold Abs.Pressure or
Bar. Pressure
Range/Performance
2) 4)
Repair Manual, 2.7 Liter V6 5V BiTurbo Engine Mechanical, Repair
Group 21; Turbocharger; Checking Charge Air Pressure Sensor -G31
2) With this malfunction the exhaust Malfunction Indicator Light (MIL) is only switched on by the ECM, if the malfunction is
recognized after the engine has been restarted. Significance of MIL Page 01
-3 .
4) Absolute manifold pressure will be determined by the Charge Air Pressure Sensor -G31 (instead of displayed -G71), the air
pressure is determined by the Barometric Pressure (BARO) Sensor -F96 (in Engine Control Module (ECM))
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