engine AUDI A4 1995 B5 / 1.G APB Engine Oxygen Sensor Control Checking User Guide
[x] Cancel search | Manufacturer: AUDI, Model Year: 1995, Model line: A4, Model: AUDI A4 1995 B5 / 1.GPages: 61, PDF Size: 0.27 MB
Page 25 of 61

24-102
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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24-103
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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Page 27 of 61

24-104
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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Page 29 of 61

24-105
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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Page 31 of 61

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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Page 33 of 61

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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Page 35 of 61

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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Page 38 of 61

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-
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Page 42 of 61

24-114
Oxygen sensor heater for oxygen
sensor, checking
Note:
The oxygen sensor heating circuit is monitored
by the On Board Diagnostic (OBD). Check DTC
memory Page 01-15
.
- 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
- Press buttons -0- and -8- to select function "Read Measuring Value
Block" and confirm entry with -Q- button.
Read Measurin
g Value Block
Input display group number XXX
Indicated on display
- Press buttons -0-, -4- and -1- to select "display group number 041" and
confirm entry with -Q- button.
Read Measuring Value Block 41
1
2
3
4
Indicated on display
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Page 43 of 61

24-115
- Adjust engine speed to approx: 3000 RPM
- Check resistance of oxygen sensor heater.
Display fields
1 2 3 4
Display Group 041: Oxygen sensor heater, Bank 1 (at idle speed)
Display
xxx kOhm
Htg.bC.ON
xxx kOhm
Htg.aC.ON
Indicates
Bank 1, Sensor 1
Status of
heater Bank 1, Sensor 2
Status of
heater
Range
Htg.bC.ON
Htg.bC.OFF
Htg.aC.ON
Htg.aC.OFF
Specified
value 0 - 0.5 kOhm
Htg.bC.ON/OFF
0 - 0.5 kOhm
Htg.aC.ON/OFF
Note
It can take a few minutes until
specification are obtained
It can take a few minutes until
specified values are obtained
- Press -C- button.
- Press buttons -0-, -4- and -2- to select "display
group number 042" and confirm entry with -Q-
button.
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