display AUDI A8 1999 D2 / 1.G AHA Engine Multiport Fuel Injection And Ignition System Service Manual

24-76

Checking

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with ignition
switched on) 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-, -0- and -4- to input display group number 4 (004),
and press -Q- button to confirm input.
Read Measuring Value Block 4 1 2 3 4

Indicated on display (1-4 = display fields)
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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.
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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
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24-79
Evaluation of display group 4 Display group: 4


Display field: 3
Possible malfunction cause
Corrective action
approx. -46.5 C
Open circuit or short circuit in wiring to B+ - Check wiring page 24
-79
approx. 141.0 C
Short circuit to Ground

Checking wiring

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

- Disconnect 4-pin connector from ECT sensor -
G62-.

- Check wiring resistance for open circuit between ECM/test box and 4-pin
ECT sensor connector.

Connector terminal 1 to ECM/test box socket 53
Connector terminal 3 to ECM/test box socket 67
Specified value: max. 1.5
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24-83

Checking

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with ignition
switched on) 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-, -0- and -4- to input display group number 4 (004),
and press -Q- button to confirm input.
Read Measuring Value Block 4 1 2 3 4

Indicated on display (1-4 = display fields)
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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.
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24-85
Evaluation of display group 4 Display group: 4


Display field: 4
Possible malfunction cause
Corrective action
constant 25.5 C
Open or short circuit in wiring to B+- Check wiring page 24
-85

Short circuit to ground
approx. ambient temperature Signal intermittently interrupted
Continuation of test page 24
-87
- Check IAT sensor

Wiring, checking:

- Switch ignition off.

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

- Disconnect 2-pin connector from Intake Air
Temperature (IAT) sensor -G42-.

- Check wiring for open circuit, between ECM/test box and 2-pin IAT harness
connector (to ECM).

Connector terminal 1 to ECM/test box socket 54
Connector terminal 2 to ECM/test box socket 67
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24-87

Continuation of test
(when IAT sensor indicates approx. ambient
temperature)

- Without disconnecting harness connector,
remove IAT sensor -G42-.

- Monitor intake air temperature value in display
field 4.

- Spray sensor with commercially available
chilling spray and check temperature value in
display field 4.

Temperature value must decrease
If NOT:

- Replace intake air temperature sensor -G42-.

- 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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24-90

Voltage supply to Engine Control
Module (ECM), 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

Checking

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with ignition
switched on) 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.
Pa
ge 115 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

Read Measurin
g Value Block
HELP
Input display group number XXX

Indicated on display
- Press buttons -0-, -0- and -4- to input display group number 4 (004),
and press -Q- button to confirm input.
Read Measuring Value Block 4 1 2 3 4

Indicated on display (1-4 = display fields)
Pa
ge 116 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