heating AUDI TT 2000 8N / 1.G ATW Engine Oxygen Sensor Control Workshop Manual

24-73


Display fields

1 2 3 4
Display group 030: Oxygen sensor status
Display
X X X X X X

Indicated
Oxygen sensor status, bank 1, sensor 1 Oxygen sensor status, bank 2, sensor 1

Functional
range 0 = off
1 = on 0 = off
1 = on

Specified
value 1 1 1 1 1 0

Note
If specified value is not obtained Page 24
-80

If specified value is obtained but there is a malfunction stored in DTC memory Check oxygen
sensor adaptation values and control, Page 24
-74

Significance of 3 digit indications in display group 030 X
X
X
Display fields 1 and 2
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 heater: 0= not active; 1 = active
Note:
The first field of the 3 digit indication (heating) fluctuates between 0 and 1.
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Continuation
If specified value in display field 1 is not obtained
or if value does not fluctuate at least 2 %:

- Road test vehicle in order to free oxygen sensor
of possible residue and repeat test.
If specified value in display field 1 is not obtained
even after road test or if value does not fluctuate
at least 2 %:

- Check primary voltage Page 24
-80
.

- Check oxygen sensor heating Page 24
-99
.

- Check oxygen sensor before catalytic converter
for aging Page 24
-83
.
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Display group 032 Display field: 1 / 2
Possible cause
Corrective action
Oxygen sensor adaptation
value in range: -10.0 to -25.0
%
Leak in intake area (pressure side between
turbocharger and intake manifold) - Check intake system for leaks and
repair false air Page 24
-68


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
-60


Evaporative Emission (EVAP) canister
purge regulator valve remains stuck in open
position - Check Evaporative Emission (EVAP)
canister purge regulator valve Page
24
-107


Fuel pressure too high- Check fuel pressure regulator Page
24
-33


Fuel injector does not close- Check fuel injectors Page 24
-38
.

Oxygen sensor heating faultyOxygen sensor faulty- Check oxygen sensor heating Page
24
-99

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Display group 032 Display field: 1 / 2
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
-68


Fuel pressure too low- Check fuel pressure regulator Page 24
-
33


Mass Air Flow (MAF) sensor faulty- Mass Air Flow (MAF) sensor, checking
Page 24
-60


Oxygen sensor heating faultyOxygen sensor faulty- Check oxygen sensor heating Page 24
-
99


Fuel injector does not open or opens
only partially - Check fuel injectors Page 24
-38
.

Evaporative Emission (EVAP)
Canister Purge Regulator Valve sticks - Check Evaporative Emission (EVAP)
canister purge regulator valve Page 24
-
107

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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

Indicated Oxygen sensor status, bank 1, sensor 1
Oxygen sensor status Bank 2, sensor 1

Functional range 0 = off
1 = on 0 = off
1 = on

Specified value 1 1 1
1 1 0

Note
If specified value is not obtained Page 24
-99

Significance of 3 digit indications in display group 030 X
X
X
Display fields 1 and 2
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 heater: 0= not active; 1 = active
Note:

Oxygen sensor control of oxygen sensor behind catalytic converter (B1-S2) is not active without engine load.
The first position of the 3 digit indication (heating) fluctuates between 0 and 1.
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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

or
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 4-pin harness connector -2- (black) to Heated Oxygen
Sensor (HO2S) -G39- before catalytic converter.
- Disconnect 4-pin harness connector -1- (brown) to Oxygen Sensor
(O2S) behind Three Way Catalytic Converter (TWC) -G130-.
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Note:
At higher temperatures, resistance climbs sharply.
If specified value is not obtained:
If specified value is obtained:
Checking voltage supply for oxygen sensor heating - Connect multimeter between terminal 1 and 2 for resistance
measurement.

Specified value at room temperature: 1 to 5
- Replace Oxygen Sensor (O2S).
- Check voltage supply of oxygen sensor heating Page 24
-101
.

- Connect multimeter between terminal 1 (B+) and 2 (Ground -GND-) for
voltage measurement.
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- Start engine.


Specification: approx. battery voltage,
possibly fluctuating

Note:

At certain operating points, the ECM "pulses"
the Ground (GND) for oxygen sensor heating.
This means that the Ground (GND) is
constantly switched on and off at these points.
It is therefore possible that the voltage
displayed on the tester will fluctuate.
When the ECM switches oxygen sensor heating
on and off can be observed, if necessary, via
the function "read measuring value block"
display group number 041.
If there is no voltage:

- Connect multimeter for voltage measurement as
follows:

Harness connector
Terminal
Measure to
1 (B+) Vehicle Ground (GND)
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Oxygen Sensor (O2S) heater -Z19- for oxygen sensor before catalytic
converter:
Oxygen sensor heater 1 -Z29- for oxygen sensor behind catalytic
converter:
If wire connection is OK, but there is no Ground (GND) supply for oxygen
sensor heating: - Check following wire connection for open circuit:Harness connector
Terminal
VAG1598/31 test box
Socket
2 5
Harness connector
Terminal
VAG1598/31 test box
Socket
2 63
- Repair open circuit if necessary.
- Replace Engine Control Module (ECM) Page 24
-23
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