1998 AUDI A4 wiring

24-122

Oxygen sensor signal wire and
activation, checking


Note:
The oxygen sensor signal is monitored by the
OBD system.

- Check DTC memory Page 01
-15
.

- If a oxygen sensor malfunction is displayed and
the oxygen sensor heater is OK, disconnect
harness connector for relevant oxygen sensor.
Component location of 4-pin harness connector
of oxygen sensor Page 24
-5 .

If the Specified value is not obtained, check oxygen sensor wiring: - Test voltage by connecting hand-held multimeter Fluke 83 (or
equivalent) (measuring range 2 V) between sockets 3 and 4 of
connector on wiring harness.
-
Switch ignition on. Specified value: 450 50 mV. Bank 1, Sensor 1 Page 24
-123
.
Bank 1, Sensor 2 Page 24
-125
.
Bank 2, Sensor 1 Page 24
-127
.
Bank 2, Sensor 2 Page 24
-129
.
Pa
ge 50 of 61 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.2

24-123
If Specified value is obtained:

- Replace relevant oxygen sensor.

Checking oxygen sensor wiring for Heated
Oxygen Sensor (HO2S) -G39
Component location of 4-pin harness connector
of oxygen sensor Page 24
-5 .

- Disconnect 4-pin connector (black) for Heated
Oxygen Sensor (HO2S) -G39.

- Connect VAG1598/31 test box to wiring harness
for engine control module. Do not connect to
engine control module itself Page 24
-20
.

Electrical Wiring Diagrams, Troubleshooting & Component Locations - Check following wiring connections for open circuits:
Connector on wiring harness,
socket
VAG1598/31 test box socket

3 51
4 70
Resistance in wiring: max. 1.5 Ohm
Pa
ge 51 of 61 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.2

24-124


Electrical Wiring Diagrams, Troubleshooting & Component Locations
Electrical Wiring Diagrams, Troubleshooting & Component Locations
If no malfunction is identified in the wiring: - Check wiring also on 4-pin harness connector for short circuits to each
other.
Connector on wiring harness,
socket
VAG1598/31 test box socket

4 51
Specified value: infinite ohms (open circuit)- Check shielded wire for short circuit to sensor wiring.
Connector on wiring harness,
socket
VAG1598/31 test box socket

4 32
3 32
Specified value: infinite ohms(open circuit)- Replace Motronic Engine Control Module (ECM) -J220 Page 24
-24
.
Pa
ge 52 of 61 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.2

24-125

Checking wiring for Oxygen Sensor (O2S)
Behind Three Way Catalytic Converter (TWC)
-G130
Component location of 4-pin harness connector
of oxygen sensor Page 24
-5 .

- Disconnect 4-pin connector (black) for Oxygen
Sensor (O2S) Behind Three Way Catalytic
Converter (TWC) -G130.

- Connect VAG1598/31 test box to wiring harness
for engine control module. Do not connect to the
engine control module itself Page 24
-20
.

Electrical Wiring Diagrams, Troubleshooting & Component Locations - Check following wiring connections for open circuits:
Connector on wiring harness,
socket
VAG1598/31 test box socket

3 68
4 69
Resistance in wiring: max. 1.5 ohm
Pa
ge 53 of 61 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.2

24-126


Electrical Wiring Diagrams, Troubleshooting & Component Locations
Electrical Wiring Diagrams, Troubleshooting & Component Locations
If no malfunction is identified in the wiring: - Check wiring also on 4-pin harness connector for short circuits to each
other.
Connector on wiring harness,
socket
VAG1598/31 test box socket

4 68
Specified value: infinite ohms (open circuit)- Check shielded wire for short circuit to sensor wiring.
Connector on wiring harness,
socket
VAG1598/31 test box socket

4 32
3 32
Specified value: infinite ohms (open circuit)- Replace Motronic Engine Control Module (ECM) -J220 Page 24
-24
.
Pa
ge 54 of 61 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.2

24-127

Checking wiring for Heated Oxygen Sensor
(HO2S) 2 -G108
Component location of 4-pin harness connector
of oxygen sensor Page 24
-5 .

- Disconnect 4-pin connector (black) for Heated
Oxygen Sensor (HO2S) 2 -G108.

- Connect VAG1598/31 test box to wiring harness
for engine control module. Do not connect to the
engine control module itself Page 24
-20
.

Electrical Wiring Diagrams, Troubleshooting & Component Locations - Check following wiring connections for open circuits:
Connector on wiring harness,
socket
VAG1598/31 test box socket

3 12
4 13
Resistance in wiring: max. 1.5 ohm
Pa
ge 55 of 61 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.2

24-128


Electrical Wiring Diagrams, Troubleshooting & Component Locations
Electrical Wiring Diagrams, Troubleshooting & Component Locations
If no malfunction is identified in the wiring: - Check wiring also on 4-pin harness connector for short circuits to each
other.
Connector on wiring harness,
socket
VAG1598/31 test box socket

4 12
Specified value: infinite ohms (open circuit)- Check shielded wire for short circuit to sensor wiring.
Connector on wiring harness,
socket
VAG1598/31 test box socket

4 32
3 32
Specified value: infinite ohms (open circuit)- Replace Motronic Engine Control Module (ECM) -J220 Page 24
-24
.
Pa
ge 56 of 61 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.2

24-129

Checking wiring for Oxygen Sensor (O2S) 2
Behind Three Way Catalytic Converter (TWC)
-G131
Component location of 4-pin harness connector
of oxygen sensor Page 24
-5 .

- Disconnect 4-pin connector for Oxygen Sensor
(O2S) 2 Behind Three Way Catalytic Converter
(TWC) -G131

- Connect VAG1598/31 test box to wiring harness
for engine control module. Do not connect to the
engine control module itself Page 24
-20
.

Electrical Wiring Diagrams, Troubleshooting & Component Locations - Check following wiring connections for open circuits:
Connector on wiring harness,
socket
VAG1598/31 test box socket

3 10
4 11
Resistance in wiring: max. 1.5 ohm
Pa
ge 57 of 61 Ox
yg
en sensor control, checkin
g
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.2