1996 AUDI A4 sensor

24-50

Checking O2S wiring, bank 2, sensor 2

- Disconnect 4-pin connector (brown) for Oxygen
Sensor (O2S) 2 behind Three Way Catalytic
Converter (TWC) -G131-.

- Connect VAG1598/22 test box to ECM harness
connector page 01
-67
.

- Check wiring for open circuit between ECM/test box and 4-pin O2S
harness connector (to ECM).

Connector terminal 3 to ECM/test box socket 38
Connector terminal 4 to ECM/test box socket 50
Specified value: max. 1.5
- Check wiring for short circuits between terminals of 4-pin connector.

Connector terminal 4 to ECM/test box socket 38
Specified value:
- Check shielding wire for short circuit to sensor wires.

Connector terminal 4 to ECM/test box socket 14
Connector terminal 3 to ECM/test box socket 14
Specified value:
Pa
ge 63 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-52

Oxygen Sensor (O2S) heater behind
TWC, checking


Notes:

Connector for Oxygen Sensor (O2S) heater
(behind TWC) -Z29- (bank 1, sensor 2): 4-pin,
green
Connector for Oxygen Sensor (O2S) 2 (behind
TWC) -Z30- (bank 2, sensor 2): 4-pin, brown
Component locations page 24
-1

Required special tools and test equipment

VAG1551 or VAG1552 Scan Tool (ST) with
VAG1551/3 adapter cable
VAG1598/22 test box
Multimeter US1119 (Fluke 83 or equivalent)
VW1594 connector test kit
Wiring diagram
Pa
ge 65 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

Test requirements

Fuse for Oxygen Sensor (O2S) heater OK
Engine Coolant Temperature (ECT) at least
80 C (176 F)
Pa
ge 66 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-54

- Compare display and specified values (display
fields 3 and 4):

Display fields

1 2 3 4
Display group 40: Oxygen Sensor (O2S) heating (before and after TWC)
Display
xx.x
Htg.bC.ON/Htg.bC.OFF
xx.x
Htg.aC.ON/Htg.aC.OFF
Indicates Resistance of O2S heater
(before TWC)
(B1-S1 and B2-S1) O2S heater ON
or
O2S heater OFF
(before TWC)
(B1-S1 and B2-S1) Resistance of O2S heater
(after TWC)
(B1-S2 and B2-S2) O2S heater ON
or
O2S heater OFF
(after TWC)
(B1-S2 and B2-S2)
Range --- ---
0.0 - 65.0
---
Specified value --- ---
2.4 - 9.2
Htg.aC.ON

--- --- If not as specified page 24
-55
, Continuation
If displayed values are OK (as specified):

-
Press button.
-
Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
Pa
ge 68 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-55

Continuation

- Disconnect 4-pin connector for respective
Oxygen Sensor (O2S) behind Three Way
Catalytic Converter (TWC).

If resistance is NOT OK:
If resistance is OK: - Connect multimeter US1119 (Fluke 83 or equivalent) between HO2S
connector terminals 1 and 2, using VW1594 connector test kit.
- Measure resistance.

Specified value: 0.00-19.9 - Replace respective Oxygen Sensor (O2S) behind TWC.
- Switch multimeter to 20 VDC measuring range.
Pa
ge 70 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-60

Oxygen Sensor (O2S) aging, bank 1,
sensor 1, checking


Required special tools and test equipment

VAG1551 or VAG1552 Scan Tool (ST) with
VAG1551/3 adapter cable

Test requirements
Engine Coolant Temperature (ECT) at least
80 C (176 F)

Function test

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with engine
running at idle) page 01
-8 .
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -4- to select "Basic Setting" function 04, and
press -Q- button to confirm input.
System in Basic Settin
g
HELP
Input display group number XXX

Indicated on display
- Press buttons -0-, -3- and -4- to input display group number 34 (034),
and press -Q- button to confirm input.
Pa
ge 75 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-61

- Increase engine speed to 1800-2200 RPM.

- Maintain engine speed at 1800-2200 RPM until
display field 4 changes from "Test OFF" to "Test
ON."

- Maintain engine speed at 1800-2200 RPM and
compare display with specified values for
oxygen sensor aging (before TWC) in display
fields 3 and 4).

Note:
To be sure that the temperature is within the
specified range, the specified RPM has to be
maintained for at least 1 minute.

Display fields

1 2 3 4
Display group 34: Oxygen sensor aging (time period check of oxygen sensor) bank 1, sensor 1
Display xxxx RPM xx.xx ms xx.xx s Test OFF/Test ON
B1-S1 OK/B1-S1 n.OK
Indicates Engine speed
(in 40 RPM steps) Engine load Time period
Bank 1, Sensor 1 Diagnostic status
Diagnostic result
Range 0 - 6800 RPM 0.00 - 12.75 ms --- ---
Pa
ge 77 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1

24-62

Continuation
If displayed value is NOT OK (not as specified):

- Road test to condition oxygen sensor (eliminate
possible contamination) and repeat test.
If displayed value is still NOT OK:

- Replace HO2S -G39-.

- Check readiness code page 01
-70
. If
Diagnostic Trouble Code (DTC) memory has
been erased, or ECM was disconnected,
generate new readiness code page 01
-73
.
Pa
ge 79 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
ystem
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1