1999 AUDI A4 wiring

01-49

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

Malfunction repair
P0156 / 16540
O2 Sensor Circuit
Malfunction (Bank 2
Sensor 2) Harness connector for Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) loose or corroded due to moisture
in the harness connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean, installation
location page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
MIL Status:
MIL lights up
immediately
Wiring connection to Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) faulty, or sensor -G131- faulty

- Check O2S 2 behind three way
catalytic converter -G131- (B2-S2)
page 24
-53


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting
Display group 041
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 "P0156 / 16540" is set 123 sec after engine start, at a coolant temperature over 80 C (176 F) and 45 sec
Pa
ge 65 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-50

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

Malfunction repair
P0158 / 16542
O2 Sensor Circuit High
Voltage (Bank 2 Sensor
2) Harness connector for Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) loose or corroded due to moisture
in the harness connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean, installation
page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
MIL Status:
MIL lights up
immediately
Wiring connection to Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) faulty, or sensor -G131- faulty

- Check O2S 2 behind three way
catalytic converter -G131- (B2-S2)
page 24
-53


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting
Display group 041
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 "P0158 / 16542" is set 3 min after engine start, as soon as the O2S voltage is greater than 1.4 volts for
Pa
ge 67 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-51

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

Malfunction repair
P0161 / 16545
O2 Sensor Heater Circuit
Malfunction (Bank 2
Sensor 2) Harness connector for Oxygen Sensor
(O2S) heater -Z30- (B2-S2) loose or
corroded due to moisture in the harness
connector

- Check harness connector for tight fit and
contact corrosion, if necessary reconnect
and/or clean, installation page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
MIL Status:
MIL lights up immediately
Wiring connection for Oxygen Sensor
(O2S) heater -Z30- (B2-S2) or heater -Z30-
(B2-S2) faulty

- Check O2S heater -Z30- (B2-S2)
page 24
-55


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting
Display group 040
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 heater for O2S behind Three Way Catalytic Converter (TWC) is not switched on immediately at engine start, but only
when the calculated exhaust gas temperature exceeds 308 C (586 F) ( Read measuring value block, display group 42,
channel 1).
Pa
ge 69 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-69


Metal chips on engine speed (RPM) sensor -G28- or
distance from the engine speed (RPM) sensor -G28- to the
flywheel ring greater than 1.2 mm (0.049 in.)

- Remove engine speed (RPM) sensor -G28-,
check for contamination, clean if necessary

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check DTC
memory again

Wiring connection to engine speed (RPM) sensor -G28-
faulty or sensor -G28- faulty

- Check and adjust engine speed (RPM) sensor -
G28- page 28
-21


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check DTC
memory again

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:
If the malfunction "P0322 / 16706" is recognized during engine start, no ignition or fuel injection occurs.
Pa
ge 93 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-71


Wiring connection to Knock Sensor (KS) 1 -
G61- faulty, or sensor -G61- faulty

- Check knock sensor 1 -G61- page 28
-29

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check DTC memory again

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 "P0327 / 16711" is set if the output voltage of the knock sensor is too low (below 0.2 V) (coolant temperature
over 20 C (68 F)/ engine speed greater than 3500 RPM and engine load greater than 16%). The ignition angle is then
retarded by 12 crankshaft in the knocking areas of the map (engine load greater than 40%).
Pa
ge 96 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-73


Wiring connection to Knock Sensor (KS) 2 -
G66- faulty or sensor -G66- faulty

- Check knock sensor 2 -G66- page 28
-29

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and after test drive, check DTC
memory again

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 "P0332 / 16716" is set when the knock sensor output voltage is too low (under 0.2 V) (coolant temperature
over 20 C (68 F) / engine speed greater than 3500 RPM and engine load greater than 16%). The ignition angle is then
retarded by 12 crankshaft in the knocking ranges of the map (engine load greater than 40%).
Pa
ge 99 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-74

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

Malfunction repair
P0337 / 16721
Crankshaft Position
Sensor Circuit Low
Input Harness connector for Crankshaft Position
(CKP) sensor -G4- loose or corroded due to
moisture 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 and after
test drive, check DTC memory again
MIL Status:
MIL lights up
immediately Crankshaft Position (CKP) sensor -G4-
loose or distance to groove on crankshaft
counterweight greater than 1.3 mm (0.053
in.)

- Check crankshaft position sensor -G4- for
correct installation and tight fit

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and after
test drive, check DTC memory again

Wiring connection to Crankshaft Position
(CKP) sensor -G4- faulty, or sensor -G4-
faulty

- Check crankshaft position sensor -G4-
page 28
-19


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and after
test drive, check DTC memory again
Pa
ge 100 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-83

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

Malfunction repair
P0452 / 16836
Evaporative Emission
Control System Pressure
Sensor Low Input Harness connector on sensor for EVAP
canister -G172- (differential pressure sensor)
loose or corroded due to 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 and
after test drive, check DTC memory
again
MIL Status:
MIL lights up immediately Wiring connection to sensor for EVAP
canister -G172- (differential pressure sensor)
faulty, or sensor -G172- faulty

- Check sensor for EVAP canister -
G172- (differential pressure sensor)
page 24
-61


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
after test drive, check DTC memory
again
For troubleshooting
Display group 030
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 "P0542 / 16836" is set as soon after engine start as the differential pressure sensor signal is less than 0.1 V
Pa
ge 111 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1