1998 AUDI A4 sensor

24-95

Note:
This procedure can take a few minutes

Display fields

1 2 3 4
Display field 034: Diagnostic oxygen sensor aging (Bank 1)
Display xxxx/RPM
xxx C
x.x s
Test ON
Indicated Engine speed
(RPM) Exhaust
temperature Period duration
oxygen sensor before catalytic
converter Diagnostic condition
Working
range 0 - 6800
70 - 850 C
0 - 3.0 Seconds
Test OFF
Test ON
B1-S1 OK
B1-S1 not OK
Specification 1900 - 2200/RPM greater than 260
C
0.1 - 1.0 s
B1-S1 OK
Note


If specified value is not obtained Continuation Page
Page 24
-96

Note for display field 2:
Calculated value from engine speed and engine load.
Note for display fields 3 and 4:
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.24.2

Period duration is the time between two voltage jumps (e.g. rich - lean - rich) and is therefore a measurement of the aging
condition of the oxygen sensor. If the specified time is exceeded, display field 4 will indicate =B1-S1 not OK.
Pa
ge 18 of 61 Ox
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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

24-96

Continuation
If specified value in display field 3 or 4 is not
obtained:

- Replace Heated Oxygen Sensor (HO2S) before
Three Way Catalytic Converter Bank 1 -G39.

Test sequence for oxygen sensor 1 before
catalytic converter bank 2

- Connect vehicle diagnostic, testing and
information system VAS5051 or VAG1551 and
select engine electronics control module by
entering address word "01" Page 01
-9. When
doing this the engine must be at idle.
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -4- to select "Basic Setting" and confirm with -Q-
button.
Pa
ge 19 of 61 Ox
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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e=re
pair&id=AUDI.B5.FU04.24.2

24-97

Basic Settin
g
Q
Input display group number XXX

Indicated on display
Test requirements - Press -0-, -3- and -5- to select "display group number 035" and confirm
with -Q- button.
Engine runs at 1900 - 2200 RPM
System in Basic Setting 35
1
2
3
4

Indicated on display
Note:
This procedure can take a few minutes - Continue test as soon as display field 4 indicates "Test ON".
Pa
ge 20 of 61 Ox
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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

24-98


Display fields

1 2 3 4
Display field 035: Diagnostic oxygen sensor aging (Bank 2)
Display xxxx/RPM
xxx C
x.x s
Test ON
Indicated Engine speed
(RPM) Exhaust
temperature Period duration oxygen sensor before
catalytic converter Diagnostic
condition
Working
range 0 - 6800
70 - 850 C
0 - 3.0 Seconds
Test OFF
Test ON
B1-S1 OK
B1-S1 not OK
Specification 1900 - 2200/RPM greater than 260
C
0.1 - 1.0 s
B1-S1 OK
Note


If specified value is not obtained Continuation Page
Page 24
-99

Note for display field 2:
Calculated value from engine speed and engine load.
Note for display fields 3 and 4:
Period duration is the time between two voltage jumps (e.g. rich - lean - rich) and is therefore a measurement of the aging
condition of the oxygen sensor. If the specified time is exceeded, display field 4 will indicate =B2-S1 not OK.
Pa
ge 21 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

24-99

Continuation
If specified value in display field 3 or 4 is not
obtained:

- Replace Heated Oxygen Sensor (HO2S) before
Three Way Catalytic Converter Bank 2 -G108.
Pa
ge 22 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

24-100


Oxygen sensor and oxygen sensor control
behind catalytic converter, checking

Test equipment and shop tools

Fluke 83 (or equivalent)
VAG1594 A
VAG1598/31
VAG1788/10
VAS5051 with VAS5051/1
- or
VAG1551 with VAG1551/3B
Pa
ge 23 of 61 Ox
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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e=re
pair&id=AUDI.B5.FU04.24.2

24-101

Notes:

Oxygen sensor control behind the catalytic
converter is responsible for final control
correction. It is the primary sensor and can
override the signal from the oxygen sensor
control before the catalytic converter..

Component location of harness connectors Page 24
-5
It corrects slight changes in the mixture (i.e. enrichment) via the
oxygen sensor before catalytic converter by holding the oxygen
sensor control before catalytic converter at its higher or lower limit for
a specific time (duration). If this time is in the positive range (i.e. 50
ms), mixture is shifted in the -enrich- direction. If this time is in the
negative range (i.e. -50 ms), mixture is shifted in the -lean- direction.
Pa
ge 24 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