1996 AUDI A4 AHA Engine Multiport Fuel Injection And Ignition System Workshop Manual

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
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Test requirements

Fuse for Oxygen Sensor (O2S) heater OK
Engine Coolant Temperature (ECT) at least
80 C (176 F)
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24-53

Checking

- 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 -8- to select "Read Measuring Value Block"
function 08, and press -Q- button to confirm input.
Read Measurin
g Value Block
HELP
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -4- and -0- to input display group number 40 (040),
and press -Q- button to confirm input.
Read Measuring Value Block 40 1 2 3 4

Indicated on display (1-4 = display fields)
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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
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input.

- Switch ignition off.
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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.
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24-56


If display = Htg.aC.ON:
If display is switching between "Htg.aC.ON" and "Htg.aC.OFF" - Connect multimeter between harness connector terminals 1 and 2 (to
ECM), using VW1594 connector test kit.
- Measure voltage supply and check display in display group 40, display
field 4.
Specified value: 11.0-14.5 volts Specified value: 0.0-12.0 volts (oscillating)
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24-57
If there is no voltage:

If there is still no voltage: - Connect multimeter between harness connector terminal 1 (to ECM)
and vehicle Ground, using VW1594 connector test kit.
Specified value: 11.0-14.5 volts
- Check wiring between terminal 1 and relay panel using appropriate
wiring diagram.
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