2000 AUDI A8 wiring

24-48
If there is no voltage:

If there is still no voltage: - Connect multimeter between harness connector terminal 1 (to ECM)
and vehicle Ground, using VW 1594 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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24-50
If there is no voltage:

- Connect VAG 1598/22 test box to ECM harness
connector Page 01
-56
.

If wiring is OK: - Check wiring for open circuit between ECM/test box and 4-pin HO2S
harness connector (to ECM).

Connector terminal 2 to ECM/test box socket 28
Specified value: max. 1.5
- Replace ECM -J220- Page 01
-57
- Carry out adaptation of throttle valve control module to ECM Page
24
-119
.
- Check readiness code Page 01
-59
. If Diagnostic Trouble Code
(DTC) memory has been erased, or ECM was disconnected, generate
new readiness code Page 01
-62
.
Pa
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24-57

Mass Air Flow (MAF) sensor, checking


Required special tools and test equipment

VAG 1551 or VAG 1552 Scan Tool (ST) with
VAG 1551/3 adapter cable
VAG 1598/22 test box
Multimeter US 1119 (Fluke 83 or equivalent)
VW 1594 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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Open circuits in wiring 3 or 4 between MAF sensor and
ECM - Check voltage supply Page 24
-61


Open circuit in wiring 1 or 2 between MAF sensor and
ECM - Check wiring Page 24
-61
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24-61

Checking voltage supply

If there is no voltage:
Checking wiring - Disconnect 4-pin harness connector from Mass Air Flow sensor (MAF).
- Connect multimeter US 1119 (Fluke 83 or equivalent) between harness
connector terminals 1 and 3 (to ECM), using adapter cables from VW
1594 connector test kit.
Specified value: 9.0-14.5 volts
- Switch ignition off.
- Check wiring using applicable wiring diagram.
- Switch ignition off.
- Connect VAG 1598/22 test box to ECM harness connector Page 01
-
56
.

- Check wiring for open circuits between ECM/test box and 4-pin MAF
sensor harness connector.

Connector terminal 2 to ECM/test box socket 12
Connector terminal 4 to ECM/test box socket 13
Specified value: max. 1.5
Pa
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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pair&id=AUDI.B5.FU02.24.1

24-62

- Check wiring for short circuits between terminals
of 4-pin connector, and between connector and
ECM/test box.


Connector terminal 4 to ECM/test box
socket 12

Specified value:

- Switch multimeter to 20 VDC measuring
range.

- Check wiring at 4-pin connector for short circuit
to B+ (battery positive voltage), according to
applicable wiring diagram.


Connector terminal 2 to vehicle Ground

Connector terminal 4 to vehicle Ground

Specified value: 0 volts
If wiring is OK:

- Replace Mass Air Flow sensor (MAF) -G70-.

-
Check readiness code Page 01
-59
. If
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) and i
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p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
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pair&id=AUDI.B5.FU02.24.1

24-63

Engine Coolant Temperature (ECT)
sensor, checking


Required special tools and test equipment

VAG 1551 or VAG 1552 Scan Tool (ST) with
VAG 1551/3 adapter cable
VAG 1598/22 test box
Multimeter US 1119 (Fluke 83 or equivalent)
VW 1594 connector test kit
Wiring diagram

Test requirements
Engine cold
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24-65

- Compare display with specified value for engine
coolant temperature sensor (display field 2):

Display fields

1 2 3 4
Display group 1: Basic function, engine idle speed
Display xxxx RPM
xxx.x C
xx.x% XXXXXX
Indicates Engine
speed
(in 40 RPM
steps) Engine coolant temperature Oxygen sensor control Adjustment
conditions
Range 0-6800
RPM -46.5 to 141.0 C
-25.0 to 25.0 % ---
Specified
value 0 RPM
approx. ambient temperature
1)
Between -10.0 and 10.0%, value
must fluctuate by at least 2 % ---

--- If not as specified Page 24
-66
,
Evaluation of display group 1
--- ---
1) If indicated temperature deviates significantly from the ambient temperature, check ECT sensor wiring for resistance or
open circuits.

- Start engine and let run at idle.

Temperature value must increase evenly
Pa
ge 86 of 135 Motronic Multi
port Fuel In
jection
(MFI
) and i
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11/19/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU02.24.1