Atmospheric pressure sensor (539), T8
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Atmospheric pressure sensor (539), T8
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(The pressure sensor is fitted only on certain cars during MY04.)
Atmospheric pressure sensor (539)
The atmospheric pressure sensor informs the control module of the prevailing atmospheric pressure. This pressure is used to calculate the smoke limitation. The higher the car's altitude, the less oxygen is in the air. So the fuel supply must be reduced. The atmospheric pressure also controls the turbo pressure which at greater altitudes must be reduced so that the turbo does not spin too fast.
The pressure sensor is a piezo-resistive sensor with its own electronics for signal amplification and temperature compensation.
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Pin No.
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Signal type
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Description
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1
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Power supply, 5V
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Connected to ECM pin 42(A).
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2
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Ground
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Connected to ECM pin 30(A).
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3
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Signal
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Connected to ECM pin 8(A).
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The electronics in the sensor are of the semiconductor type and mounted on chips, which on changes in air pressure bend and thus pass more or less voltage depending on the external air pressure.
