engine AUDI A4 1999 B5 / 1.G AWM Engine Oxygen Sensor Control Checking Workshop Manual
[x] Cancel search | Manufacturer: AUDI, Model Year: 1999, Model line: A4, Model: AUDI A4 1999 B5 / 1.GPages: 46, PDF Size: 0.3 MB
Page 2 of 46
24-72
Test requirements:
Exhaust system free of leaks.
Coolant Temperature at least 80 C.
Test sequence
- Connect VAS5051 tester Page 01
-7 and
select vehicle system "01 - Engine electronics".
Engine must run at idle for this.
Display on VAS5051:
- In selection -1-, click on the diagnostic function "04 - Basic setting".
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Page 3 of 46
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Display on VAS5051:
1 - Enter display group Max. input value = 255
- Select function "030" in button field -2- for "display group number 030"
and press Q button to confirm input.
Display on VAS5051:
Notes: - Check specified value in display field -1-.
Increase engine speed to obtain specified values faster. "Oxygen sensor status" indicates status of oxygen sensor control and
oxygen sensors.
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Page 6 of 46
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-
Press button to change into display group
033.
- Check oxygen sensor control in display fields -1-
and -2-.
Display fields
1 2 3 4
Display group 033: Oxygen sensor control
Display
xx.x %
x.xxx V
Indicated
Oxygen sensor control bank 1, sensor 1
Oxygen sensor voltage, Bank 1, sensor 1
Specified
value Value must fluctuate at least 2 % in the
range -10.0 to 10.0 % 0.130 to 3.600 volts
Note
If specified value is not obtained
Continuation, Page 24
-77
If specified value is not obtained Evaluation
display group 033, Page 24
-80
Note for display field 2:
The oxygen sensor voltage signal which is processed and calendered by the Engine Control Module (ECM) will be displayed.
1.5 volts in display corresponds to Lambda 1.
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Page 12 of 46
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If specified value is not obtained:
- Check oxygen sensor wiring.
If specified value is obtained:
- Replace Heated Oxygen Sensor (HO2S)-G39-
.
Checking oxygen sensor wires
Note:
Coolant reservoir screws must be removed and coolant reservoir must be
placed to side in order to access the harness connector. The coolant
hoses can remain connected. - Disconnect 6-pin harness connector (black) -2- to Heated Oxygen
Sensor (HO2S) -G39- before catalytic converter.
- Connect VAG1598/31 test box at wiring harness to Engine Control
Module (ECM), do not connect ECM Page 24
-19
.
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Page 13 of 46
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Electrical Wiring Diagrams, Troubleshooting & Component Locations
If wire connection is OK: - Check the following wire connections for open circuit.Harness connector
Terminal
VAG1598/31 test box
Socket
1 70
2 71
5 51
6 52
- Repair open circuit if necessary.- Check wires to each other for short circuit.
- Replace Engine Control Module (ECM) Page 24
-22
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Page 15 of 46
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Test sequence
- Connect VAS5051 tester Page 01
-7 and
select vehicle system "01 - Engine electronics".
Engine must run at idle for this.
Display on VAS5051:
- In selection -1-, click on the diagnostic function "04 - Basic setting".
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Page 16 of 46
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Display on VAS5051:
1 - Enter display group Max. input value = 255
- Select function "034" in button field -2- for "display group number 034"
and press Q button to confirm input.
- Use VAG1788/10 RPM adjuster to adjust engine speed to between
2300 and 2800 RPM.
Display on VAS5051:
Note:
This process can take a few minutes. - Check specified value in display field -4-.
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Page 17 of 46
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Display fields
1 2 3 4
Display group 034: Diagnostic oxygen sensor aging
Display xxxx/min
xxx C
x.x
---
Indicated Engine speed
(RPM) Exhaust
temperature Dynamic factor Diagnostic condition
Functional
range
Test OFF
Test ON
B1-S2 OK
B1-S2 not OK
Specified value 2300 to 2800 RPM
larger than 350 C
0.5 to 2.5 B1-S2 OK
Note
If specified value is not obtained Continuation, Page
24
-88
Note for display field 2:
Calculated value from engine speed and engine load.
Note for display fields 3 and 4:
The dynamic factor is a characteristic for oxygen sensor aging. The smaller the dynamic factor, the further the oxygen sensor
aging process has advanced.
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Page 22 of 46
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If specified value is obtained:
- Check voltage supply of oxygen sensor
heating.
Checking voltage supply for oxygen sensor
heating
Note:
When the Engine Control Module (ECM) switches oxygen sensor heating
on and off, it may be observed via the function "read measuring value
block", in display group number 041 display field 2.
If there is no voltage: - Connect multimeter between terminal 3 and 4 for voltage
measurement.
- Start engine.
Specification: approx. battery voltage
- Connect multimeter for voltage measurement as follows.Harness connector
Terminal
Measure to
3 (B+) Vehicle Ground (GND)
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Page 23 of 46
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- Operate starter briefly.
Specification: approx. battery voltage
If there is no voltage again:
- Check wire connection from terminal 3 of
connector to Fuel Pump (FP) relay via fuse for
open circuit:
Electrical Wiring Diagrams, Troubleshooting &
Component Locations
If voltage supply is OK:
Note: - Connect multimeter for voltage measurement as follows:Harness connector
Terminal
Measure
to
4 (Ground -GND- activation of Engine Control Module -
ECM-) B+
- Start engine.
Specification: approx. battery voltage
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