1996 AUDI A8 coolant

24-63

Oxygen Sensor (O2S) aging, bank 2,
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 -5- to input display group number 35 (035),
and press -Q- button to confirm input.
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24-68

Mass Air Flow (MAF) sensor, checking


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

Test requirements
All electrical consumers switched off (coolant
fan must not run during test).
A/C must be switched off
Fuse for MAF sensor OK
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24-75

Engine Coolant Temperature (ECT)
sensor, checking


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

Test requirements
Engine cold
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24-77

- Compare display with specified value for engine
coolant temperature sensor (display field 3):

Display fields

1 2 3 4
Display group 4: General engine data
Display xxx RPM xx.xxx V
xxx.x C
xxx.x C
Indicates Engine
speed
(in 40 RPM
steps) Battery Positive
Voltage (B+) Engine coolant temperature Intake air
temperature
Range 0 - 6800
RPM 0.000 - 16.500 V -46.5 to 141.0 -46.5 to 141.0
Specified
value 0 RPM 10.000 - 14.500 V approx. ambient temperature 1), 2) ---

--- --- If specified value is not attained page 24
-79
,
Evaluation of display group 4
---
1) After a long standing period (approx. 12 hours). 2) If indicated temperature deviates significantly from the ambient temperature, check ECT sensor wiring for resistance or
open circuits.
Pa
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24-78

Continuation

- Start engine and let run at idle.

Temperature value must increase evenly
If NOT:

-
Press button.

- Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
input.

- Switch ignition off.

- Replace Engine Coolant Temperature (ECT)
sensor -G62-.

Notes:

Temperature is displayed in increments of 1.5
C.

If malfunctions occur within certain temperature
ranges while the engine is running, and the
temperature values do not increase without
interruption, the temperature signal is
Pa
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24-81
If wiring is OK:

- Check ECT sensor resistance across terminal 1 (signal) and terminal 3
(ground).
- Check measured resistance value for appropriate temperature range
using graph below (N24-0157).

Range A: 0-50 C (32-122 F)

Range B: 50-100 C (122-212 F)

Examples:
If resistance is NOT OK:
At 30 C, ECT sensor resistance should be 1500-2000 At 80 C, ECT sensor resistance should be 275-375
- Replace Engine Coolant Temperature (ECT) sensor -G62-.
- 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
.
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24-84

- Compare displayed value with specified value
for intake air temperature (display field 4):

Display fields

1 2 3 4
Display group 4: General engine data
Display xxx RPM xx.xxx V
xxx.x C
xxx.x C
Indicates Engine speed
(in 40 RPM
steps) Battery Positive
Voltage (B+) Engine coolant
temperature Intake air temperature
Range 0 - 6800 RPM 0.000 - 16.500 V -46.5 to 141.0 -46.5 to 141.0
Specified
value 0 RPM 10.000 - 14.500 V --- approx. ambient temperature 1), 2)

--- --- --- Continuation page 24
-85
, Evaluation of
display group 4
1) After a long standing period (approx. 12 hours). 2) If indicated temperature deviates significantly from the ambient temperature, check IAT sensor wiring for resistance or open
circuits.
Pa
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24-91

- Check battery positive voltage (B+) in display
field 2.

Display fields

1 2 3 4
Display group 4: General engine data
Display xxx RPM xx.xxx V
xxx.x C
xxx.x C
Indicates Engine speed
(in 40 RPM
steps) Battery Positive Voltage (B+)
Terminal 15 Engine coolant
temperature Intake air
temperature
Range 0 - 6800 RPM 0.000 - 16.500 V -46.5 to 141.0 -46.5 to 141.0
Specified
value 0 RPM 10.000 - 14.500 V --- ---

--- If not as specified page 24
-92
, Evaluation
of display group 4
--- ---
If displayed value is OK (as specified):

-
Press button.
- Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
input.
Pa
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) and i
gnition s
ystem
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yp
e=re
pair&id=AUDI.B5.FU03.24.1