The Intake Air Temperature (IAT) sensor measures the temperature of engine intake air. The Intake Air Temperature (IAT) sensor is a thermistor (a variable resistor that changes along with outside air temperature) in series with a fixed resistor in the PCM. The PCM applies 5volts to the IAT sensor. The PCM monitors the voltage across the IAT sensor and converts it into a temperature reading. When the outside air temperature is cold the IAT sensor resistance is high, and when the outside air temperature is warm the IAT sensor resistance is low. Therefore, when the air temperature is cold the PCM will receive a high voltage input, and when the air temperature is warm the PCM will receive a low voltage input. The signal from IAT sensor is used for injection time correction (Cold post start correction), ignition angle correction(Air temperature correction) and idle speed correction(Air-density correction).
If the value of IAT sensor output is higher than 50 kΩ, the PCM determines that a fault exists and a DTC is stored.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Resistance of sensor is monitored | ● Poor connection ● Open or short to battery in IAT sensor circuit ● Faulty IATS ● Faulty PCM |
Enable Conditions | ● Time after cranking > 2sec | |
Threshold value | ● Resistance, Rats ≥50kΩ(4.57V) | |
Diagnosis Time | ● Continuous |
Temperature(℃/℉) | -40/-40 | -30/-22 | -20/-4 | 0/32 | 20/68 | 80/176 | 100/212 | 110/230 | 120/248 |
Resistance(kΩ) | 45.3 | 25.6 | 15.1 | 5.8 | 2.5 | 0.33 | 0.19 | 0.16 | 0.13 |
Voltage(V) | 4.48 | 4.34 | 4.12 | 3.46 | 2.57 | 0.64 | 0.39 | 0.34 | 0.27 |
