engine AUDI A4 1999 B5 / 1.G AWM Engine Oxygen Sensor Control Checking User Guide
[x] Cancel search | Manufacturer: AUDI, Model Year: 1999, Model line: A4, Model: AUDI A4 1999 B5 / 1.GPages: 46, PDF Size: 0.3 MB
Page 24 of 46
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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Page 25 of 46
24-93
- Switch ignition off.
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
.
Electrical Wiring Diagrams, Troubleshooting & Component Locations
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
4 5
- Repair open circuit if necessary.- Replace Engine Control Module (ECM) Page 24
-22
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Page 28 of 46
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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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Page 30 of 46
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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
-107
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
Notes:
The first position of the 3 digit indication (heating) fluctuates between 0 and 1.
Oxygen sensor control of oxygen sensor after catalytic converter (B1-S2) is not active without engine load.
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Page 31 of 46
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Display on VAS5051:
Checking oxygen sensor control after catalytic converter
Test requirement: - Do not continue test until indication in display field -2- has reached
"110" at least once.
Engine continues to run at 2600 RPM.
-
Click on - button
Display on VAS5051:
1 - Enter display group Max. input value = 255
- Select function "037" in button field -2- for "display group number 037"
and press -Q- button to confirm input.
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Page 33 of 46
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Display fields
1 2 3 4
Display group 037: Diagnostic oxygen sensor control system
Display xxx %
x.xxx V
x.xx
---
Indicated Engine
load Oxygen sensor voltage
Bank 2, sensor 1 Oxygen sensor correction value
between bank 1, sensor 1 and
bank 1, sensor 2 Diagnostic condition
Functional
range
Test OFF
Test ON
System OK
System not OK
Specified
value 13 to 40
% 0.100 to 0.950 volts
smaller than 0.02 System OK
Note
If specified value is not
obtained: Evaluation
Page 24
-102
If "System not OK" is
displayed: Check DTC
memory Page 01
-12
Note for display field 2:
Oxygen sensor voltage bank 1, sensor 2 should remain fairly constant. Strong voltage fluctuations point to a damaged
catalytic converter.
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Page 37 of 46
24-105
If specified value is not obtained:
- Check oxygen sensor wiring.
If specified value is obtained:
- Replace Oxygen Sensor (O2S) behind Three
Way Catalytic Converter (TWC) -G130-.
Checking oxygen sensor wires
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-.
- Connect VAG1598/31 test box at wiring harness to Engine Control
Module (ECM), do not connect ECM Page 24
-19
.
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Page 38 of 46
24-106
Electrical Wiring Diagrams, Troubleshooting & Component Locations
If wire connection is OK: - Check the following wire connections for open circuit.Harness connector
Terminal
VAG1598/31 test box
Socket
3 68
4 69
- Repair open circuit if necessary.- Check wires to each other for short circuit.
- Replace Engine Control Module (ECM) Page 24
-22
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Page 42 of 46
24-109
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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Page 43 of 46
24-110
- Operate starter briefly.
Specification: approx. battery voltage
If there is no voltage again:
- Check wire connection from terminal 1 of
connector to Fuel Pump (FP) relay via fuse for
open circuit:
Electrical Wiring Diagrams, Troubleshooting &
Component Locations
If voltage supply is OK:
- Connect multimeter for voltage measurement as follows:Harness connector
Terminal
Measure
to
2 (Ground -GND- activation of Engine Control Module -
ECM-) B+
- Start engine.
Specification: approx. battery voltage, possibly fluctuating
- Switch ignition off.
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