wiring AUDI A4 1998 B5 / 1.G AFC Engine On Board Diagnostic Multiport Fuel Injection Workshop Manual

01-4

Malfunction Indicator Lamp (MIL),
functions


Functional testing:
The Malfunction Indicator Lamp (MIL) must light up every time the
ignition is switched on and go out after the engine starts. If a
malfunction is recognized by the engine control module or the
transmission control module, this is indicated by the MIL lighting up. If the MIL lights up continuously, there is a malfunction present that
makes the exhaust gas worse. In this case, the DTC memory for the
engine control module and/or the transmission control module should
be checked. If the MIL starts to blink, there is a malfunction that can lead to
damage of the three way catalytic converter (e.g. combustion misfiring
with high misfiring rate). In this case, driving should only continue with
reduced power (until the MIL goes off or lights up continuously) and
the malfunction should be eliminated as quickly as possible.
- Switch ignition on: the MIL must light up. If the MIL does not light up,
check wiring according to wiring diagram and/or replace lamp.
- Start engine and let idle: MIL must go out after a couple seconds. If the
MIL does not go out after the engine starts, check DTC memory for the
engine and/or transmission control modules (malfunctions in DTC
memory).
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01-5
Malfunction recognition and repair

Notes:

Before initiating the On Board Diagnostic (OBD) program, and before testing wiring and replacing components, check the
following ground connections for corrosion and damaged connections and repair them if necessary
- Check ground connections on intake manifold
- Battery ground strap OK
- Ground cable between engine and body OK Malfunction recognition and repair is described for the VAG 1551 scan tool, since it offers significantly more functions.
However, malfunction recognition and repair is also possible with a "generic" scan tool.
A specific procedure must be used to evaluate malfunctions, since the engine electronics can be checked with address
word 01 and address word 33 on OBD II vehicles. Address word 33 can only be used to check malfunctions that have
already switched on the Malfunction Indicator Light (MIL). Address word 01 can also display the malfunctions that have
not switched on the MIL. In contrast to before, the MIL is not switched on immediately with some malfunction types, but
only after two successive trips with cold starts preceding them where the malfunction occurs. If there is a customer
complaint and/or driving performance problem, the DTC memory should be checked thoroughly with address word 01,
function 02. On vehicles with MIL lit up, the DTC memory should also be checked with address word 33, mode 3. If the
DTC memory is checked with mode 3, mode 2 should also be checked which shows the operating conditions as they were
when the malfunction was recognized.
If a malfunction is present for longer than a specified time, the malfunction is stored as a static malfunction. Malfunctions
that never or immediately switch the MIL on are set as "sporadic" at each engine start. If the malfunction occurs again, the
"sporadic" status is erased again. The "sporadic" status is erased exclusively after an OK diagnosis for malfunctions that
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Electrical Wiring Diagrams, Troubleshooting & Component Locations Additional operating instructions can be obtained by using the VAG
1551 scan tool HELP button. The button is used to advance to the next program step.
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01-10

Rapid data transfer
Q
01 - Engine Electronics

Indicated on display
- Press -Q- button to confirm input.
Rapid data transfer Scan Tool sends address word 01

Indicated on display
_________________________________________________________
Rapid data transfer
HELP
Control module does not answer

If the following is shown on the display:
Notes:
Electrical Wiring Diagrams, Troubleshooting & Component Locations - A list of possible malfunction causes can be printed out by pressing the
HELP button.
Check data link connector/engine control module wiring connection:Engine control module faulty Diagnostic Trouble Code (DTC) table,
page 01
-26
.
Rapid data transfer
HELP
Error in communication link

If the following is shown on the display:
Notes:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
On vehicles with several On Board Diagnostic (OBD) systems, check
wiring connection between the individual systems: For vehicles with only MFI (Engine Electronics) On Board Diagnostic
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01-11

Rapid data transfer
HELP
K wire not switching to Ground

If one of the following two problems is shown on the display
Rapid data transfer HELPK wire not switching to B+

Note:
Check data link connector/engine control module wiring connection:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
_________________________________________________________ - A list of possible malfunction causes can be printed out by pressing the
HELP button. - After the malfunction cause is repaired, insert address word 01 again
and press -Q- button to confirm input.
8D0906266 2.8l V6/2V MFI OBD2
D01
Codin
g 01051
WSC 06388

The control module identification and the coding are shown on the
display:
Engine control module replacement part no. 8D0906266
For current engine control module version Parts catalog
Engine displacement: 2.8 liters Engine construction type: V-engine, 6-cylinderValves per cylinder: 2 valvesFuel injection system: Multiport Fuel Injection (MFI)Engine control module software version: OBD2, EPROM-status
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If faulty components are found, also check wiring to the components according to wiring diagram for short and open
circuit.
Before repairing or replacing components, check ground connections for Engine Control Module (ECM) -J192- connector
D on terminals 3, 7 and 12 and connector E on terminals 3, 7 and 11 (specified value approx. 0.5 ) and ground points on
the engine for corrosion and damage, check fuel pump relay Repair Group 24.
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01-27

Output on GST and/or
on VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0102 / 16486
Mass or Volume Air Flow
Circuit Low Input Harness connector on Mass Air Flow
(MAF) sensor -G70- loose or corrosion
because of moisture in the harness
connector

- Check harness connector for tight fit and
contact corrosion, if necessary reconnect
and/or clean

Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after test
drive check DTC memory again
MIL Status:
MIL lights up immediately Wiring connection to Mass Air Flow (MAF)
sensor -G70- faulty or sensor -G70- faulty

- Check Mass Air Flow (MAF) sensor -
G70- page 24
-81


Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after test
drive check DTC memory again
For troubleshooting
Display groups 000, 001,
019
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control module
page 01
-265
erase DTC memory
and test drive check DTC memory
Note:
The malfunction "P0102 / 16486" is set as soon as the signal voltage drops below 0.5 volts for longer than 0.3 sec (engine
speed under 2000 RPM).
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01-28

Output on GST and/or
on VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0103 / 16487
Mass or Volume Air Flow
Circuit High Input Harness connector on Mass Air Flow
(MAF) sensor -G70- loose or corroded due
to dampness in the harness connector

- Check harness connector for tight fit and
contact corrosion, if necessary retighten
and/or clean

Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after test
drive check DTC memory again
MIL Status:
MIL lights up immediately Wiring connection to Mass Air Flow
(MAF) sensor -G70- faulty or sensor -G70-
faulty

- Check Mass Air Flow (MAF) sensor -
G70- page 24
-81


Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after test
drive check DTC memory again
For troubleshooting
Display groups 000, 001,
019
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control module
page 01
-265
erase DTC memory and
test drive check DTC memory
Note:
The malfunction "P0103 / 16487" is set as soon as the signal voltage rises above 5 volts for longer than 0.5 sec (engine
speed below 2000 RPM).
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01-29

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0116 / 16500
Engine Coolant Temperature
Circuit Range/Performance
Problem Harness connector on Engine Coolant
Temperature (ECT) sensor -G62- loose or
corroded due to dampness in the harness
connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean, installation
location page 28
-7

Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after
test drive check DTC memory again
MIL Status:
MIL lights up immediately Wiring conection to Engine Coolant
Temperature (ECT) sensor -G62- faulty,
or sensor -G62- faulty

- Engine Coolant Temperature (ECT)
sensor -G62-, checking page 28
-25


Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after
test drive check DTC memory again
For troubleshooting Display
groups 000, 001
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Notes:
The malfunction "P0116 / 16500" is set as soon as the coolant temperature lies under 55 C (131 F) after engine start, but
18 minutes later the temperature has not risen to over 70 C (158 F).
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01-30

Output on GST and/or
on VAG 1551 scan tool
Possible malfunction cause

Malfunction repair
P0117 / 16501
Engine Coolant
Temperature Circuit
Low Input Harness connector on Engine Coolant
Temperature (ECT) sensor -G62- loose or
corroded due to dampness in the harness
connector

- Check harness connector for tight fit and
contact corrosion, if necessary reconnect
and/or clean, installation location page 28
-7

Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after test
drive check DTC memory again
MIL Status:
MIL lights up
immediately Wiring connection to Engine Coolant
Temperature (ECT) sensor -G62- faulty, or
sensor -G62- faulty

- Engine Coolant Temperature (ECT)
sensor -G62-, checking page 28
-25


Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after test
drive check DTC memory again
For troubleshooting
Display groups 000,
001
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control module
page 01
-265
erase DTC memory and
test drive check DTC memory
Notes:
The malfunction "P0117 / 16501" is set as soon as the signal voltage drops below 0.10 volts for longer than 1 sec when
ignition is switched on (corresponds to a coolant temperature over 200 C (392 F).
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