Intake Air Temperature Sensor

The temperature sensor is located in the intake manifold and is NTC type. The control module measures the air temperature in the intake manifold by supplying 5 V to the sensor 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 temperature of the intake air.

The temperature is used to:
- 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.
- 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. A more advanced ignition is required at low temperatures.
- Blocking the OBD II diagnosis: at starting temperatures lower than -7 °C.
- Block OBD II diagnosis at temperatures lower than -7 °C.
- Reactivate OBD II diagnosis at temperatures higher than 5 °C.

Diagnostics
- It the sensor voltage is too low, diagnostic trouble code P0112 will be generated.
- It the sensor voltage is too high, diagnostic trouble code P0113 will be generated.
- The control module sets a substitute value of 40 °C.

System reaction to a fault
- Density compensation of the throttle angle is blocked.