AUDI A4 1999 B5 / 1.G APB Engine Oxygen Sensor Control Checking Owner's Manual

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.
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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.
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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
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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.
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Test conditions

Perform road test and do not erase DTC
memory.
Coolant temperature at least 85 C (185 F)
(Display group 004, display field 3)

- Connect vehicle diagnostic, testing and
information system VAS5051 or VAG1551 scan
tool 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
Note:
During the basic setting the Evaporative Emission (EVAP) canister purge
regulator valve -N80 is closed and the A/C compressor is switched off. - Press buttons -0- and -4- to select function "Basic Setting" and confirm
entry with -Q- button.
Basic Settin
g
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -3- and -4- to select "display group number 034" and
confirm entry with -Q- button.
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System in Basic Setting 34
1
2
3
4

When indicated on display:
Note:
This process can take a few minutes. - Adjust engine speed using VAG1788/10 to 2800 - 3200 RPM.
- Continue test as soon as display field 2 indicates an exhaust
temperature of more than 320 C. - Press -C- button.
- Adjust engine speed using VAG1788/10 to 1900 - 2200 RPM.
Basic Settin
g
Q
Input displa
y group number XXX

When indicated on display:
- Press buttons -0-, -3- and -0- to select "display group number 030" and
press -Q- button to confirm input.
System in Basic Setting 30
1
2
3
4

When indicated on display:
Note:
"Oxygen sensor status" indicates status of oxygen sensor control and
oxygen sensor. - Check oxygen sensor status for oxygen sensor behind catalytic
converter in display field 2.
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Display fields

1 2 3 4
Display group 030: Oxygen sensor status with engine at idle
Display X X X
X X X X X X
X X X
Indicated Oxygen sensor status,
bank 1, sensor 1 Oxygen sensor status
bank 1, sensor 2 Oxygen sensor status,
bank 2, sensor 1 Oxygen sensor status
bank 2, sensor 2
Working
area 0 = off
1 = on 0 = off
1 = on 0 = off
1 = on 0 = off
1 = on
Specified
value: 1 1 1
1 1 1 1 1 1
1 1 1
Note:
Significance of display Page 24
-105


If specified value is not obtained:
Check oxygen sensor signal wire and activation Page 24
-122

Check oxygen sensor heater Page 24
-114

Notes:

Oxygen sensor control of oxygen sensor behind catalytic converter (Bank 1-Sensor 2 and Bank 2 -Sensor 2) is not active
without engine load.
The first position of the 3 digit indication (heater) fluctuates between 0 and 1.
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The third position of the 3 digit indication (oxygen sensor control) fluctuates between 0 and 1.
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Significance of 3 digit indication in Display Group 030 1
1
1
Display fields 1 to 4
X Oxygen sensor control
0= inactive
1= active
X Operational readiness of oxygen sensor
0= inactive
1= active
X Condition of oxygen sensor heater
0= inactive
1= active

- Press -C- button.Basic Setting
Q
Input displa
y group number XXX

When indicated on display
Test requirements - Press buttons -0-, -4- and -3- to select "display group number 043" and press -Q-
button to confirm input.
Engine runs at 1900 - 2200 RPM
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System in Basic Setting 43
1
2
3
4

When indicated on display
- Check specified value in display field 4.
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