2000 AUDI A4 sensor

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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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Continuation
If specified value in display field 3 and 4 is not
obtained:

- Road test vehicle in order to free oxygen sensor
of possible residue and repeat test.
If specified value in display field 3 and 4 is not
obtained, even after road test:

- Replace Heated Oxygen Sensor (HO2S)-G39-
.
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Oxygen sensor heating, Oxygen Sensor
(O2S) Heater -Z19- before catalytic
converter, checking

Special Tools and Equipment

VAG1526A
VAG1594A
VAG1598/31
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Test requirements:

Coolant Temperature at least 80 C.

Fuse for oxygen sensor heating OK

Electrical Wiring Diagrams, Troubleshooting &
Component Locations

Test sequence

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.

If specified value is not obtained: - Connect multimeter between terminal 3 and 4 for resistance
measurement.

Specified value at room temperature: 2.5 to 10
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- Replace Heated Oxygen Sensor (HO2S)-G39-.
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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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- 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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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.
Pa
ge 24 of 46 Ox
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11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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e=re
pair&id=AUDI.B5.FU07.24.2