sensor AUDI A4 1998 B5 / 1.G AHA Engine Multiport Fuel Injection And Ignition System Repair Manual

intermittently interrupted and the sensor must
be replaced.
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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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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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24-82

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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- 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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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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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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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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24-88

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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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
.
Pa
ge 114 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