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 ECM. The ECM applies 5V to the IAT sensor. The ECM 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 ECM will receive a high voltage input, and when the air temperature is warm the ECM will receive a low voltage input. The signal from IAT sensor is used for injection duration correction, ignition timing correction and idle speed correction(Air-density correction).
If measured temperature is lower than the minimum threshold value during 2sec, ECM sets DTC P0113.(In this case, the input signal voltage is the maximum threshold vaue.)
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal check, high
Poor connection
Open or short to power in signal circuit
Open in ground circuit
IATS
Enable Conditions
Idle and no fuel cut-off
Time after engine start > 18s
Integrated air mass > 0.36kg
Increase of measured temp. after start < 1.5?
Threshold Value
Measured temperature < -43.5 ?
Diagnostic Time
2 sec
MIL ON Condition
3 driving cycle
Temperature [°C (°F)]
Resistance [kO]
-40(-40)
40.93~48.35
-30(-22)
23.43~27.34
-20(-4)
13.89~16.03
-10(14)
8.50~9.71
0(32)
5.38~6.09
10(50)
3.48~3.90
20(68)
2.31~2.57
25(77)
1.90~2.10
30(86)
1.56~1.74
40(104)
1.08~1.21
60(140)
0.54~0.62
80(176)
0.29~0.34