Intake air temperature sensor
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Intake air temperature sensor
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The NTC-type temperature sensor is located in the intake manifold. The control module measures the air temperature in the intake manifold by supplying the sensor with 5V through an integrated 2.74 kohm resistor from pin 15. The sensor is grounded from pin 22. The voltage across the resistor in the control module is proportional to the intake air temperature.
The temperature is used to:
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Determine the density of the charge air together with charge air pressure. The charge air density is used by the air mass control to correct the throttle angle.
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Correct the PWM ratio of the charge air control valve. A higher PWM ratio is required at high temperatures to obtain the same air mass/combustion.
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Correct the ignition timing. A more advanced ignition is required at low temperatures.
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Blocking of OBD II diagnosis:
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Block the OBD ll diagnosis at lower temperatures than -7°C.
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Reactivate the OBD ll diagnosis at higher temperatures than +5°C
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If the sensor voltage is too low, diagnostic trouble code P0112 will be generated.
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If the sensor voltage is too high, diagnostic trouble code P0113 will be generated.
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The control module sets 40°C as a substitute value.
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System reaction to a fault
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Density compensation of the throttle angle is blocked.
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