Engine Controls - Intake Air Temperature Sensor
SOURCE: Kia Technician TimesTITLE: Intake Air Temperature Sensor
APPLIES TO: 98 Sephia
98 Sportage
SERVICE TIP:
A separate Intake Air Temperature (IAT) Sensor has been added to the 1998 Sephia and Sportage to further enhance fuel and emission control. This sensor was part of the MAF on prior vehicles.
This sensor is installed on the air cleaner and detects intake air temperature. The IAT sending unit employs a thermistor (a resistor which changes value based on changes in air temperature) to monitor the temperature of air entering the engine. Sensitive to any change in temperature, thermistor resistance:
- Decreases in response to a temperature increase
- Increases in response to a temperature decrease
A voltage signal based on this resistance is sent to the ECM, which then calculates the intake air temperature based on the voltage signal received. High resistance in the sensor will result in a low voltage signal to the ECM. Low resistance in the sensor will result in a higher voltage signal to the ECM. The ECM will monitor the IAT circuit for OBD-II related malfunctions in two areas:
- An open or short to battery voltage between the IAT sensor signal line and the ECM
- An open circuit between the IAT sensor ground line and the ECM