display AUDI A4 1995 B5 / 1.G ATQ Engine Oxygen Sensor Control Checking
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24-79
Notes:
For the defined troubleshooting procedure, it is
possible, to switch oxygen sensor control off by
selecting display group 099 under "basic
setting" and switch it on again under "read
measuring value block".
After selecting display group 099 (either in
"basic setting" or "read measuring value
block"), it is possible to switch back and forth
between "basic setting" (function 04) and "read
measuring value block" (function 08) by
pressing buttons 4 or 8 on the VAG1551.
Once function 04 "basic setting" is exited,
oxygen sensor control is automatically switched
on again.
Test requirements:
Road test performed and DTC memory
erased.
Coolant temperature at least 80 C
Display group 4, display field 3
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Function test
- Connect VAS5051 tester or VAG1551 scan tool
and select the control module for engine
electronics using "address word" 01 Page 01
-
9 .
Engine must run at idle for this.Rapid data transfer
HELP
Select function XX
When indicated on display:
Note:
During basic setting, the Evaporative Emission (EVAP) canister purge
regulator valve (EVAP valve -N80-) is closed and the A/C compressor is
switched off - Press buttons -0- and -4- to select "Initiate basic setting" and press -Q-
button to confirm input.
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: - Check oxygen sensor status in display fields 1 and 3.
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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 2, sensor 1 Oxygen sensor status,
bank 2, sensor 1 Oxygen sensor status,
bank 2, sensor 2
Functional
range 0 = off
1 = on 0 = off
1 = on 0 = off
1 = on 0 = off
1 = on
Specified
value 1 1 1 1 1 0
1 1 1 1 1 0
Notes
Meaning of display Page 01
-90
If specified value is not obtained Page 24
-89
If specified value is obtained but there is a malfunction stored in DTC memory Check oxygen
sensor adaptation values and control, page Page 24
-83
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Significance of 3 digit indication of display group 030 X
X
X
Display fields 1 to 4
X Oxygen sensor control
0= not active
1 = active
X Operational readiness of oxygen sensor
0= not active
1 = active
X Condition of oxygen sensor heating
0= not active
1 = active
Notes:
The oxygen sensor control of the oxygen sensors behind catalytic converter (B1-S2 and B2-S2) are not active at certain
operation points without engine load, that means that the third position of the oxygen sensor controls behind catalytic
converter can fluctuate between 0 and 1.
The first position of the 3 digit indication (heating) fluctuates between 0 and 1 at certain operation points.
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Checking oxygen sensor adaptation values
and control
- Press -C- button.Basic Setting
Q
Input displa
y group number XXX
When indicated on display:
- Press buttons -0-, -3- and -3- to select "display group number 033" and
press -Q- button to confirm input.
System in Basic Setting 33
1
2
3
4
When indicated on display:
- Check oxygen sensor control in display fields 1 and 3.
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1 2 3 4
Display group 033: Oxygen sensor control before catalytic converter
Display
xx.x % x.xxx volts
xx.x % x.xxx V
Indicated
Oxygen sensor control
Bank1 Oxygen sensor voltage
bank 1 Oxygen sensor control
Bank2 Oxygen sensor voltage
bank 2
Functional
range -25.0 to 25.0 % 0.100 to 1.000 V
-25.0 to 25.0 % 0.100 to 1.000 V
Specified
value Value must fluctuate by
at least 2 % in the range
10.0 to 10.0 % Value must fluctuate
approx. 0.3 V in the
range 0.100 to 1.000
volts Value must fluctuate by
at least 2 % in the range
10.0 to 10.0 % Value must fluctuate
approx. 0.3 V in the
range 0.100 to 1.000
volts
Notes
If specified value is not
obtained Page 24
-85
If specified value is not
obtained Page 24
-85
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Evaluation display group 033 Display field: 1 / 3
Possible cause
Corrective action
Values in range:
-10.0 to -25.0 %
Oxygen sensor heating faulty- Check oxygen sensor heating Page
24
-116
or
Values in range:
Open circuit in wires between oxygen sensor
and control module - Check primary voltage Page 24
-89
10.0 to 25.0 %
or
Value does not fluctuate
by at least 2 %
Short circuit to Ground (GND) or B+ between
oxygen sensor and control module - Check oxygen sensor wires bank 1
Page 24
-90
- Check oxygen sensor wires bank 2
Page 24
-91
False air in intake area- Check intake system for leaks and
repair false air Page 24
-64
Fuel pressure too low or too high- Check fuel pressure regulator Page
24
-30
Fuel return line is kinked or clogged- Check fuel return line.
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- Press -C- button.
- Press buttons -0-, -3- and -2- to select "display
group number 032" and press -Q- button to
confirm input. System in Basic Setting 32
1
2
3
4
When indicated on display:
- Check oxygen sensor control in display fields 1 to 4:
Display fields
1 2 3 4
Display group 032: Oxygen sensor adaptation values before catalytic converter
Display
xx.x %
xx.x %
xx.x %
xx.x %
Indicated
Oxygen sensor
adaptation value
Bank 1 at idle
(additive) Oxygen sensor adaptation
value bank 1 at partial
throttle
(multiple) Oxygen sensor
adaptation value
Bank 2 at idle
(additive) Oxygen sensor adaptation
value bank 2 at partial
throttle
(multiple)
Functional
range -25.0 to 25.0 %
-25.0 to 25.0 %
-25.0 to 25.0 %
-25.0 to 25.0 %
Specified
value -10.0 to 10.0 %
can fluctuate
slightly -10.0 to 10.0 %
can fluctuate slightly -10.0 to 10.0 %
can fluctuate
slightly -10.0 to 10.0 %
can fluctuate slightly
Notes
If specified value is not obtained Page 24
-87
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Evaluation display group 032 Display field:
1 / 3 or 2 / 4
Possible cause
Corrective action
Oxygen sensor
adaptation value in
range:
-10.0 to .-25.0 %
Oil thinning- Oil change or perform swift country road
test
High oil consumption
Mass Air Flow (MAF) sensor faulty- Mass Air Flow (MAF) sensor, checking
Page 24
-56
Evaporative Emission (EVAP) canister purge
regulator valve remains stuck in open position - Check Evaporative Emission (EVAP)
Canister Purge Regulator Valve Page 24
-
128
Fuel pressure too high- Check fuel pressure regulator Page 24
-
30
Fuel return line is kinked or clogged.- Check fuel return line.
Fuel injector does not close- Check fuel injectors Page 24
-36Pa
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Evaluation display group 032 Display field:
1 / 3 or 2 / 4
Possible cause
Corrective action
Oxygen sensor
adaptation value in range:
10.0 to 25.0 %
False air in intake area- Check intake system for leaks and repair false
air.
Page 24
-64
.
Fuel pressure too low- Check fuel pressure regulator Page 24
-30
Mass Air Flow (MAF) sensor faulty- Mass Air Flow (MAF) sensor, checking
Page 24
-56
Oxygen sensor heating faulty
Oxygen sensor faulty- Check oxygen sensor heating Page 24
-116
Fuel injector does not open or opens
only partially - Check fuel injectors Page 24
-36
Evaporative Emission (EVAP) Canister
Purge Regulator Valve sticks - Check Evaporative Emission (EVAP) Canister
Purge Regulator Valve Page 24
-128
Ignition coil or spark plug faulty- Check ignition coils Page 28
-7
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