1998 AUDI A4 catalytic converter

24-113

Continuation
If the specified value in display group 037 and
038, display 3 or 4 is not obtained:

- Check exhaust system and catalytic converter
for leaks (check clamps and exhaust for
damage)

- If the difference of the values in measuring
blocks, display fields 3 (oxygen sensor
correction value) is to large (e.g.:+500 ms, -500
ms), it is possible that the oxygen sensor are
interchanged (mixed up).
If none of the causes are identified:

- Replace particular oxygen sensor "before"
catalytic converter.
Pa
ge 41 of 61 Ox
yg
en sensor control, checkin
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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

24-120

Heated Oxygen Sensor (HO2S) -G39
Connector on wiring
harness, socket
VAG1598/31 test
box, socket
2 5 (Ground)
Heated Oxygen Sensor (HO2S) 2 -G108
Connector on wiring
harness, socket
VAG1598/31 test
box, socket
2 4 (Ground)
Oxygen Sensor (O2S) Behind Three Way
Catalytic Converter (TWC) -G130
Connector on wiring
harness, socket
VAG1598/31 test
box, socket
2 63 (Ground)
Oxygen Sensor (O2S) 2 Behind Three Way
Catalytic Converter (TWC) -G131
Connector on wiring
harness, socket
VAG1598/31 test
box, socket
2 6 (Ground)
Resistance in wiring: max. 1.5 Ohm

Electrical Wiring Diagrams, Troubleshooting &
Component Locations
Pa
ge 48 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

24-129

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

24-132

Oxygen sensors, removing and
installing


Removing

- Disconnect harness connector of particular
oxygen sensor before catalytic converter for
bank 1 and bank 2 (component location Page
24
-5 ).

- Disconnect harness connector of particular
oxygen sensor behind catalytic converter for
bank 1 and bank 2 (component location Page
24
-5 ).

- Remove particular oxygen sensor with 3337/7
special tool.

- Lower transmission, in order to remove oxygen
sensors behind catalytic converter.

Repair Manual, 6 Spd. Manual Transmission
01E, Repair Group 34, Transmission removing and installing.

Pa
ge 60 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