heating AUDI A4 1997 B5 / 1.G AWM Engine Oxygen Sensor Control Checking User Guide
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Oxygen sensor heating, Oxygen Sensor
(O2S) Heater 1 -Z29- after 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 4-pin harness connector -1- (brown) to Oxygen Sensor
(O2S) behind Three Way Catalytic Converter (TWC) -G130-.
If specified value is not obtained: - Connect multimeter between terminal 1 and 2 for resistance
measurement.
Specified value at room temperature: 6.4 to 47.5
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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 4.
If there is no voltage: - Connect multimeter between terminal 1 (B+) and 2 (Ground -GND-) for
voltage measurement.
- Start engine.
Specification: approx. battery voltage
- Connect multimeter for voltage measurement as follows:Harness connector
Terminal
Measure to
1 (B+) Vehicle Ground (GND)
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If there is no voltage:
- Connect VAG1598/31 test box at wiring harness
to Engine Control Module (ECM), do not connect
ECM Page 24
-19
.
If wire connection is OK, but there is no Ground (GND) supply for oxygen
sensor heating: - Check the following wire connection for open circuit:Harness connector
Terminal
VAG1598/31 test box
Socket
2 63
- Repair open circuit if necessary.
- Replace Engine Control Module (ECM) Page 24
-22
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