Intake air temperature sensor
|
|
Intake air temperature sensor
|
The temperature sensor (407) is positioned in the intake manifold in front of the throttle and is of NTC type. The control module measures the air temperature in the intake manifold by feeding the sensor 5 V through a 2.74 kohm resistor in the control module from pin 15. The sensor is grounded from pin 70. The voltage across the resistor in the control module is proportional to the intake air temperature.
The pressure sensor and temperature sensor functions (603) are integrated in the same component.
The temperature is used to:
|
•
|
Determine, together with the charge air pressure, the density of the charge air. The charge air density is used by the air mass control to correct the throttle angle.
|
|
•
|
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.
|
|
•
|
Correct the ignition timing. At low temperatures, more advanced ignition is required.
|
|
•
|
Block OBD II diagnostics at temperatures below -7°C.
|
|
•
|
If the sensor voltage is too low, diagnostic trouble code P0112 will be generated.
|
|
•
|
If the sensor voltage is too high, diagnostic trouble code P0113 will be generated.
|
|
•
|
The control module sets 40°C as a substitute value.
|
System reaction to a fault
|
•
|
Density compensation of the throttle angle is blocked.
|
