ESP AUDI A4 1995 B5 / 1.G ATQ Engine Oxygen Sensor Control Checking

24-89

Checking primary voltage
Component location of harness connectors
Overview of component locations, page Page
24
-5

Note:
Coolant reservoir screws must be removed and
coolant reservoir must be placed to side in order
to access this harness connector. The coolant
hoses can remain connected.

Test requirement:

Fuse for oxygen sensor are OK

- Disconnect 4-pin harness connector leading to
respective oxygen sensor.

If specified value is not obtained: - Connect multimeter between terminal 3 and 4 for voltage
measurement.
- Switch ignition on.

Specification: 0.400 to 0.500 V
- Switch ignition off.
-
Check oxygen sensor wires Bank 1, page Page 24
-90
or Bank Pa
ge 15 of 63 Ox
yg
en sensor control, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.3

24-110

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

- Search for leaking air at exhaust system or
catalytic converter (check screw clamps and
exhaust system for damage).

- Check if possibly the oxygen sensors behind
catalytic converter of cylinder bank 1 and 2 have
been switched, in case of extremely different
values (e.g. +500 ms, - 500 ms) of display fields
3 (oxygen sensor correction value) in the
measuring value blocks 037 and 038.
If none of the listed causes applies:

- Replace respective oxygen sensor -before-
catalytic converter
Pa
ge 42 of 63 Ox
yg
en sensor control, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.3

24-111

Checking primary voltage
Component location of harness connectors
Overview of component locations - page Page
24
-5

- Disconnect 4-pin harness connector leading to
respective oxygen sensor.

If specified value is not obtained:
If specified value is obtained: - Connect multimeter between terminal 3 and 4 for voltage
measurement.
- Switch ignition on.

Specification: 0.400 to 0.500 V
- Switch ignition off.
- Check oxygen sensor wires Bank 1 page Page 24
-112
or bank 2
page Page 24
-114
.
- Replace appropriate oxygen sensor behind catalytic converter.
Pa
ge 43 of 63 Ox
yg
en sensor control, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.3

24-121

Checking voltage supply for oxygen sensor
heating

Test requirement:

Fuse for oxygen sensor heating OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder

Fuel Pump (FP) OK, checking Page 24
-
49
.
Component location of harness connectors
Overview of component locations, page Page
24
-5

- Disconnect 4-pin harness connector leading to
respective oxygen sensor.

- Connect multimeter between terminal 1 and 2 for voltage
measurement.
Pa
ge 56 of 63 Ox
yg
en sensor control, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.3

24-126

Oxygen sensor, removing and installing


Special tools and equipment

Removing
Component location of harness connectors Overview of component
locations, page Page 24
-5
3337 wrench, 7-piece set Locking compound G 052 112 A3
- Disconnect 4-pin harness connector leading to respective oxygen
sensor.
- Open cable ties.
- Unscrew oxygen sensor using special tool 3337.
Pa
ge 62 of 63 Ox
yg
en sensor control, checkin
g
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.24.3