AUDI A4 1995 B5 / 1.G APB Engine Oxygen Sensor Control Checking User Guide

24-89

If the specified values in display fields 1
and/or 3 do not match the specifications, or if
the readout does not fluctuate by at least 2
%:

- Check oxygen sensor heater Page 24
-114
.

- Check oxygen sensor signal wire and activation
Page 24
-122
.

- Check intake system for leaks and eliminate
false air Page 24
-76
.

- Check fuel pressure regulator Page 24
-33
.

- Fuel return line kinked or plugged.

-
Press button.
- Press button -0- and -6- to select function "End
Output" and confirm with -Q- button.

- Switch ignition off.
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Evaluation display group 032 Display group 32


Display fields: 1/3
Possible cause
Corrective action
Oxygen sensor adaptation
values in range:
-4.0 to -25.0 %
Oil thinning- Carry out oil change or carry out
road test on highway
Display fields: 2/4
High oil consumption
Oxygen sensor adaptation
values in range:
-4.0 to -25.0 % Mass Air Flow (MAF) Sensor faulty- Check Mass Air Flow (MAF) Sensor
Page 24
-59


EVAP canister purge regulator valve remains in
stuck in open position - Check EVAP canister purge
regulator valve Page 24
-134


Fuel pressure too highFuel return line kinked or pluged- Check fuel pressure regulator
Page 24
-33

- Check fuel return line

Fuel injector leaking- Check fuel injectors Page 24
-39
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24-91
Evaluation display group 032 Display Group 32


Display fields: 1/3
Possible cause
Corrective action
Oxygen sensor adaptation
values in range:
4.0 and 25.0 %
Un-metered air in intake area- Check intake system for un-metered
air and eliminate leaks
Display field: 2/4
Fuel pressure too low- Check fuel pressure regulator Page
24
-33

Oxygen sensor adaptation
values in range:
4.0 - 25.0 %
Oxygen sensor heater faulty- Check oxygen sensor heater Page
24
-114


Injector not opening or only opening partially - Check injectors Page 24
-39

EVAP canister purge regulator valve remains
in stuck in open position - Check EVAP canister purge
regulator valve Page 24
-134
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24-92
Evaluation display group 33 Display Group
33


Display field:
2/4
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
More than
1.100 V
Short to B+ in wire 4 between oxygen sensor and
control module - Check oxygen sensor wiring, bank 1, sensor
1 Page 24
-123

Less than
0.100 V
Short to Ground (GND) in wire 4 between oxygen
sensor and control module - Check oxygen sensor wiring, bank 2, sensor
1 Page 24
-127

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24-93

Oxygen sensors aging, oxygen sensor
before catalytic converter, checking


Test requirements

Coolant temperature min. 85 C (185 F)
(Display group 004, display field 3)

Test sequence for oxygen sensor 1 before
catalytic converter bank 1

- 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.
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24-94

Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -4- to select "Basic Setting" and confirm with -Q-
button.
Basic Setting
Q
Input displa
y group number XXX

Indicated on display
Test requirements - Press -0-, -3- and -4- to select "display group number 034" and confirm
with -Q- button.
Engine runs at 1900 - 2200 RPM
System in Basic Setting 34
1
2
3
4

Indicated on display
- Continue test as soon as display field 4 indicates "Test ON".
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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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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.
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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.
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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".
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