1996 AUDI A8 checking

24-82

Intake Air Temperature (IAT) 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
Chilling spray (commercially available)
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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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24-85
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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24-88

Engine Speed (RPM) sensor, checking


Note:
Component locations page 24
-1

Required special tools and test equipment

VAG1598/22 test box
Multimeter US1119 (Fluke 83 or equivalent)
VW1594 connector test kit
Wiring diagram

Checking

- Disconnect 3-pin harness connector from engine
speed sensor.

- Connect VAG1598/22 test box to ECM harness
connector page 01
-67
.
Pa
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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
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) and i
gnition s
ystem
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e=re
pair&id=AUDI.B5.FU03.24.1

24-93

Checking voltage supply at terminal 30

- Switch ignition off.

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

- Connect multimeter US1119 (Fluke 83 or
equivalent) between ECM/test box sockets 2
(Ground) and 3 (B+), using adapter cables from
VW1594 connector test kit.

Specified value: 10-14.5 volts
If voltage is NOT OK:

- Check wiring according to applicable wiring
diagram.
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) and i
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24-94

Checking voltage supply at terminal 15

- Switch ignition off.

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

- Connect multimeter between ECM/test box
sockets 1 (B+) and 2 (Ground), using adapter
cables from VW1594 connector test kit.

- Switch ignition on, and check voltage.

Specified value: 10-14.5 volts
If voltage is NOT OK:

- Check wiring according to applicable wiring
diagram.

- 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
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24-95

Fuel pump relay and connections,
checking


The fuel pump relay is located at relay position 6 on the relay panel on the
left side under the instrument panel.
Checking function of fuel pump relay -J17-
- Remove storage shelf in left-front footwell.

- Remove fuses 28, 29 and 34 from fuse panel.
- Connect VAG1527B LED voltage tester between Ground and one of
the two terminals for fuse 28.
- Briefly crank starter.

LED test light must light up.
Fuel pump relay must be actuated (can be felt and heard)
Pa
ge 121 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