heating AUDI A8 1999 D2 / 1.G ATQ Engine Oxygen Sensor Control Checking
Page 55 of 63
24-120
If specified value is not obtained:
- Check voltage supply of oxygen sensor heating
Page 24
-121
.
- Check oxygen sensor signal wire and activation
Page 24
-112
or Page 24
-114
.
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Page 56 of 63
24-121
Checking voltage supply for oxygen sensor
heating
Test requirement:
Fuse for oxygen sensor heating OK
Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
Fuel Pump (FP) OK, checking Page 24
-
49
.
Component location of harness connectors
Overview of component locations, page Page
24
-5
- Disconnect 4-pin harness connector leading to
respective oxygen sensor.
- Connect multimeter between terminal 1 and 2 for voltage
measurement.
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Page 57 of 63
24-122
- Start engine.
Specification: approx. battery voltage,
possibly fluctuating
Notes:
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.
It is possible to observe the ECM switching
oxygen sensor heating on and off within the
function "read measuring value block", display
group numbers 041 and 042.
If there is no voltage:
- Connect multimeter for voltage measurement as follows:Harness connector
Terminal
Measure to
1 (B+) Vehicle Ground (GND)
- Operate starter briefly.
Pa
ge 57 of 63 Ox
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11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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e=re
pair&id=AUDI.B5.FU05.24.3