1999 AUDI A8 sensor

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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24-87

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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24-88

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
.
Pa
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pair&id=AUDI.B5.FU03.24.1

Fuse for fuel injectors OK
Engine speed (RPM) sensor OK
Fuel pump relay OK
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24-107

Checking

- Remove intake air hose between MAF sensor
and intake air noise muffler.

- Remove vacuum hose from Intake Manifold
Tuning (IMT) valve -N156- (change-over valve).

- Remove 5-pin connector from ignition coils, 2-
pin connector from valve for camshaft
adjustment -N208- (bank 2) and 2-pin connector
from camshaft position sensor -G163- (bank 1).

- Disconnect wiring harness from clips on fuel
rail.

- Disconnect fuel rail from intake manifold and remove fuel lines together
with injectors.
- Remove vacuum hose from fuel pressure regulator.
- Remove harness connectors from all injectors.
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24-118


Display fields

1 2 3 4
Display group 70: EVAP canister purge regulator valve
Display xxx % xx.x % xx.xx g/s Test OFF/Test
ON
EVAP OK
EVAP n.OK
Indicated EVAP canister purge regulator
valve duty cycle during diagnosis Oxygen sensor deviation
during diagnosis Idle Air Control (IAC) valve
deviation during diagnosis Diagnosis
condition
Diagnosis
results
Range 0 - 100 % -25.0 to +25.0 % -2.70 to +4.16 g/s ---
Specified
value 0 - 93 % - 15.0 to +15.0 % 1.00 - 0.00 g/s EVAP OK If "EVAP n.OK" is indicated in display field 4:

- Check for blockage or leaks page 24
-119
.
If "EVAP OK" is indicated in display field 4:

-
Press button.Rapid data transfer
HELP

Indicated on display
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24-127

Read Measuring Value Block 1 1 2 3 4

Indicated on display (1-4 = display fields)
- Monitor oxygen sensor control in display fields 3 and 4.

Display fields

1 2 3 4
Display group 1: Engine idle speed
Display xxxx RPM
xx.x C
xx.x% xx.x %
Indicates Idle speed
(in 40 RPM
steps) Engine Coolant Temperature
(ECT) Oxygen Sensor (O2S)
control, Bank 1 Oxygen Sensor (O2S)
control, Bank 2
Range 0 - 6800 RPM
-48.0 - 143.2 C
(-54 - 289 F)
-25.0 to +25.0 % -25.0 to +25.0 %
Specified
value 620 - 740
RPM
(all-wheel
drive) --- -10.0 to +10.0 %
value must change by at
least 2 % -10.0 to +10.0 %
value must change by at
least 2 %
740 - 860
RPM
(front-wheel
drive)
- Systematically spray parts of intake air system with engine leak detector spray.
Pa
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) and i
gnition s
ystem
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yp
e=re
pair&id=AUDI.B5.FU03.24.1