coolant temperature AUDI A4 1999 B5 / 1.G APB Engine Ignition System Checking

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Display fields

1 2 3 4
Display Group 004: Intake air temperature with engine idling
Display xxxx rpm xx.xxx V
xxx.x C
xxx.x C
Indicates Engine speed Battery voltage Coolant temperature
Intake air temperature
Work range min.: 750 RPM
max.: 6800 RPM min.:10.000 V
max.: 15.000 V min.: -48.0 C
max.: 143.0 C
min.: -48.0 C
max.: 143.0 C
Specified value xxxx RPM 12.000...15.000 V
80.0...110.0 C
Between ambient temp. and 120 C
1)
1) If there is a large difference between the temperature displayed and the ambient temperature at the sensor, check the
sensor and sensor wiring for contact resistance and open circuit.
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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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If the value does match the specification:

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

Coolant temperature sensor with square
connector:

Coolant temperature sensor with oval connector: - Check following wiring connections for open circuits and short circuits
to B+ or Ground (GND) Harness connector
Terminal
VAG1598/31 test box
Socket
1 (Signal) 93
3 108

- Check following wiring connections for open circuits and short circuits
to B+ or Ground (GND) Harness connector
Terminal
VAG1598/31 test box
Socket
3 108
4 (Signal) 93
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