AUDI A4 1995 B5 / 1.G APB Engine Oxygen Sensor Control Checking Owner's Guide

24-106


Display fields

1 2 3
4
Display group 043: Oxygen sensor aging oxygen sensor behind catalytic converter (Bank 1)
Display xxxx/RPM
xxx C
x.xxx V
Test ON
Indicated Engine speed
(RPM) Exhaust
temperature Voltage of oxygen sensor
behind CAT, Bank 1 Diagnostic condition
Work range 0 - 6800/RPM
70 - 850 C
0.000 - 1.000 Volt
Test OFF
Test ON
B1-S2 OK
B1-S2 not OK
Specified
value 1900 -
2200/RPM greater than 320
C 0.000 - 1.000 Volt
B1-S2 OK
Note



If specified value is not reached. Check
oxygen sensor heater Page 24
-114

If the specified value of "B1-S2 OK" is reached:

- Press -C- button.

Test requirements

Engine runs at 1900 - 2200 RPM
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- Press buttons -0-, -4- and -4- to select "display
group number 044" and press -Q- button to
confirm input.
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24-107


Display fields

1 2 3
4
Display group 044: Oxygen sensor aging oxygen sensor behind catalytic converter (Bank 2)
Display xxxx/RPM
xxx C
x.xxx V
Test ON
Indicated Engine speed
(RPM) Exhaust
temperature Voltage of oxygen sensor
behind CAT, Bank 1 Diagnostic condition
Work range 0 - 6800/RPM
70 - 850 C
0.000 - 1.000 Volt
Test OFF
Test ON
B2-S2 OK
B2-S2 not OK
Specified
value 1900 -
2200/RPM greater than 320
C 0.000 - 1.000 Volt
B1-S2 OK
Note



If specified value is not reached. Check
oxygen sensor heater Page 24
-114

If the specified value of "B2-S2 OK" is reached:

- Press -C- button.
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24-108

Checking oxygen sensor control behind
catalytic converter

- Carry out road test for approx.: 10 minutes.Basic Setting
Q
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -3- and -7- to select "display group number 037" and
press -Q- button to confirm input.
System in Basic Setting 37
1
2
3
4

Indicated on display
- Check oxygen sensor voltage in display field 2.
- Check dwell time (hold up) between oxygen sensor 1 before catalytic
converter and oxygen sensor 2 behind catalytic converter in display
field 3 and diagnostic result in display field 4.
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24-109


Display fields

1 2 3 4
Display group 037: Diagnostic oxygen sensor control (Bank 1)
Display xxx % x.xxx Volt xxx ms
Test ON
Indicated Engine
load Oxygen sensor voltage behind
catalytic converter, Bank 1 Correction value between
oxygen sensor 1 and sensor
2, bank 1 Diagnostic condition
Work
range 15.0 -
175.0 % 0.000 - 1.000 V -1200 - 1200 ms
Test OFF
Test ON
SYST. OK
SYST. not OK
Specified
value 15.0 -
25.0 % 0.000 - 1.000 V -500 - 500 ms
SYST. OK
Note

If specified value is not
obtained: Evaluation display
field 2 Page 24
-112

If specified value is
obtained: Continuation
Page 24
-113

If "SYST. not OK" is
displayed: Check DTC
memory Page 01
-15

or Continue Page 24-113

Note for display field 3:
Oxygen sensor control behind catalytic converter is superior to oxygen sensor control before catalytic converter and is the
primary control. It corrects slight changes in the mixture (i.e. enrichment or thinning) by holding the oxygen sensor control
before catalytic converter at its higher or lower point 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-
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direction.
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24-110

- Press -C- button.

- Press buttons -0-, -3- and -8- to select "display
group number 038" and press -Q- button to
confirm input. System in Basic Setting 38
1
2
3
4

Indicated on display: (1 - 4 display fields)
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24-111


Display fields

1 2 3 4
Display group 038: Diagnostic oxygen sensor control (Bank 2)
Display xxx % x.xxx Volt xxx ms
Test ON
Indicated Engine
load Oxygen sensor voltage behind
catalytic converter, Bank 2 Correction value between
oxygen sensor 1 and sensor
2, bank 2 Diagnostic condition
Work
range 15.0 -
175.0 % 0.000 - 1.000 V -1200 - 1200 ms
Test OFF
Test ON
SYST. OK
SYST. not OK
Specified
value 15.0 -
25.0 % 0.000 - 1.000 V -500 - 500 ms
SYST. OK
Note
If specified value is not obtained:
Evaluation display field 2
Page 24
-112

If specified value is obtained:
Continuation Page 24
-113

If "SYST. not OK" is
displayed: Check DTC
memory Page 01
-15

or Continue Page 24-113

Note for display field 3:
Oxygen sensor control behind catalytic converter is superior to oxygen sensor control before catalytic converter and is the
primary control. It corrects slight changes in the mixture (i.e. enrichment or thinning) by holding the oxygen sensor control
before catalytic converter at its higher or lower point 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-
Pa
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pair&id=AUDI.B5.FU04.24.2

direction.
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24-112
Evaluation display group 037 and 038 Display Group:
037/038


Display field: 2
Possible cause
Corrective action
approx.: 0.450 V

Open circuit in wire 4 between oxygen sensor
and control module - Check signal wire and activation Page 24
-
122



Open circuit in wire 3 between oxygen sensor
and control module

Oxygen sensor heater faulty
Oxygen sensor faulty- Check oxygen sensor heater Page 24
-114
- Replace oxygen sensor
greater than
1.100 V
Short circuit to B+ in wire 4 between oxygen
sensor and control module - Check oxygen sensor wiring bank 1 sensor 2
(behind converter) Page 24
-125

smaller than
0.100 V
Short circuit to Ground (GND) in wire 4 between
oxygen sensor and control module
Short circuit between wire 3 and 4- Check oxygen sensor wiring bank 2 sensor 2
(behind converter) Page 24
-129

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pair&id=AUDI.B5.FU04.24.2