Download 1241 WS4

Group 23 EDC III
Electronic fault detection
Checking the combined
sensor for charge air pressure/
temperature
Checking the coolant
temperature sensor
Checking charge air pressure
1.
Switch off the engine
2.
Disconnect the connector from the charge air
pressure sensor and connect 4-pin adapter
9998534 between the sensor connector and the
engine wiring. Then connect multimeter 9510060-8
between measurement points 1-4.
3.
Switch on the operating voltage.
4.
Measure using a multimeter set to measure voltage.
Check that the multimeter reads 5.0 volts.
5.
Then connect the multimeter between
measurement points 2-4. The voltage should be
about 1.2 V at normal atmospheric pressure.
Checking charge air temperature
1.
Disconnect the connector from the charge air
pressure sensor.
2.
Connect 4-pin adapter 9998534 between the
sensor connector and multimeter 9510060-8.
3.
Measure with the multimeter set to measure resistance between the measurement points of the
adapter.
The multimeter should show the following values:
Measurement points
Desired values
3–4
R~6.2 kΩ (20°C / 68°F)
3–4
R~ 2.5 kΩ (40°C / 104°F)
1.
Disconnect the connector and remove the
sensor from the engine.
2.
Use mulitmeter 9510060-8 to measure between
both contact pins of the sensor.
The multimeter should show the following values at:
0°C / 32°F
4930 Ω ± 440 Ω
20°C / 68°F
1870 Ω ± 140 Ω
40°C / 104°F
800 Ω ± 50 Ω
60°C / 140°F
370 Ω ± 20 Ω
80°C / 176°F
190 Ω ± 8 Ω
100°C / 212°F
104 Ω ± 4 Ω
NOTE: The sensor is extremely sensitive to changes
in temperature. When measuring in the lower temperature interval 0–40°C / 32-104°F, holding the sensor in
your hand is sufficient to make the value quickly go to
the lower resistance value.
NOTE: Even if resistance values follow those in the
above table, it is no guarantee that the sensor is faultfree.
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