1995 AUDI A4 display

24-80
Evaluation display group 033 Display field:
2
Possible cause
Corrective action
larger than
4.800 V
Short circuit to B+ in wire connections between
oxygen sensor and control module
Oxygen sensor faulty- Check oxygen sensor wires of oxygen sensor
before catalytic converter Page 24
-82

smaller than
0.130 V
Short circuit to Ground (GND) in wire connections
between oxygen sensor and control module
Oxygen sensor faulty
- Replace oxygen sensor before catalytic
converter
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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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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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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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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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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.
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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.

- Install VAG1788/10 RPM adjuster on the
accelerator pedal and raise the engine speed to
2600 RPM.

Test requirement:

Engine running at 2600 RPM.

Display on VAS5051:
- In selection -1-, click on the diagnostic function "04 - Basic setting".
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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pair&id=AUDI.B5.FU07.24.2