wiring diagram AUDI A4 1995 B5 / 1.G AHA Engine Multiport Fuel Injection And Ignition System User Guide

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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24-80


- Check wiring for short circuit between ECM/test box and 4-pin harness
connector according to wiring diagram.

Connector terminal 1 to vehicle Ground
Connector terminal 1 to ECM/test box socket 67
Connector terminal 1 to terminal 3
Connector terminal 3 to vehicle Ground
Specified value:
- Check wiring between ECM and 4-pin harness connector for short
circuit to battery B+.

Connector terminal 1 to vehicle Ground
Connector terminal 3 to vehicle Ground
Specified value: 0 volts
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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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24-86


If wiring is OK: - Check wiring for short circuit between ECM/test box and 2-pin harness
connector according to wiring diagram.

Connector terminal 1 to vehicle Ground
Connector terminal 1 to ECM/test box socket 67
Connector terminal 1 to terminal 2
Specified value:
- Check wiring between ECM and 2-pin harness connector for short
circuit to battery B+.
Specified value: 0 volts

If resistance is NOT OK: - Check resistance across terminals of IAT sensor -G42-.

Specified value at approx. 20 C (68 F): approx. 1.5-3.5 k- Replace intake air temperature sensor -G42-.
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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
.
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24-89


If wiring is OK: - Check wiring for open circuit between ECM/test box and 3-pin harness
connector.

Connector terminal 1 to ECM/test box socket 67
Connector terminal 2 to ECM/test box socket 63
Connector terminal 3 to ECM/test box socket 56
Specified value: max. 1.5
- Check wiring for short circuit between ECM/test box and 3-pin harness
connector, according to wiring diagram.

Connector terminal 2 to ECM/test box socket 67
Connector terminal 1 to ECM/test box socket 63
Connector terminal 1 to ECM/test box socket 56
Specified value:
- Replace engine speed (RPM) sensor -G28-.
- 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.
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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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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
.
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24-96
If the fuel pump does not respond:

- Check fuel pump relay actuation page 24
-
99
.
If the LED test light does not light up:

- Repeat test at other terminal of fuse 28.

If the LED light still does not light up:
- Check wiring for open or short circuits between fuse 28 and terminal 30
at relay position 6, using the applicable wiring diagram. Repair wiring
as necessary.

Specified value: max. 1.5

Note:
This step lets the fuel pump run without the engine running. The closed
throttle position switch must be closed during the test, or the selected fuel
injector will discharge fuel when it is actuated 5 times. - Connect VAG1527B LED voltage tester between Ground and one of
the two terminals for fuse 29.
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p://127.0.0.1:8080/audi/servlet/Dis
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yp
e=re
pair&id=AUDI.B5.FU03.24.1