1998 AUDI A4 APB Engine Ignition System Checking

follows:
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- Connect VAG1598/31 test box to wiring harness
for engine control module. Do not connect to the
engine control module itself Page 24
-20
.

Specified value: max. 1 .
Specified value: max. 1 .
Specified value: max. 1 . - Test continuity of screening (shielded wire) between contact 1 on
engine speed sender connector and socket 108 on test box. - Test continuity of negative wire from contact 2 on sender connector to
socket 90 on test box. - Test continuity of signal wire from contact 3 on sender connector to
socket 82 on test box.
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If the values are not as specified:

- Rectify short or open circuit in wiring between
sender connector and control module connector.

Terminal on sensor
connector
Terminal on control
module connector
1
2
3 108
90
82

- If no open circuits or short circuits are identified,
replace Engine Control Module (ECM) Page
24
-24
.
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Engine Coolant Temperature (ECT)
sensor -G62, checking


Note:
Component location of coolant temperature
sensor Page 24
-5 .

Test conditions

Engine cold

- Connect vehicle diagnostic, testing and
information system VAS 5051 or VAG1551 scan
tool to vehicle and select engine electronics
control module by entering address word "01"
Page 01
-9 .

When doing this the engine must be at idle.
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Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select function "Read Measuring Value
Block" and confirm entry with -Q- button.
Read Measuring Value Block Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -0- and -4- to select Display Group 4 and confirm
entry with -Q- button.
Read Measuring Value Block 4
1
2
3
4

Indicated on display
- Check readout for coolant temperature sender in display field 3.
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Display fields

1 2 3 4
Display Group 004: Coolant temperature with engine idle
Display xxxx RPM xx.xxx V
xxx.x C
xxx.x C
Indicates Engine speed RPM Battery voltage
Coolant temperature Intake air temperature
Specified value XXXX RPM 12.000...14.500 V
Temperature must increase evenly Ambient temperature
until 120 C
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If display field 3 does not display a realistic
value:

- Disconnect harness connector from coolant
temperature sensor.

Coolant temperature sensor with square
connector:

- Connect multi-meter (resistance measurement) between terminals 1
and 3 of sensor.
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Coolant temperature sensor with oval
connector:

All:
Scale A shows resistance values for temperature range 0 - 50 C and
scale B the values for temperature range 50 - 100 C. - Connect multi-meter (resistance measurement) between terminals 3
and 4 of sensor.

Examples:
If value does not match the specification:
30 C corresponds to a resistance from 1500...2000 80 C corresponds to a resistance from 275...375
- Replace coolant temperature sensor.
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