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 sensor voltage is higher than the maximum threshold value, 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
IG ON
Battery voltage 10~16V
Threshold Value
Intake air temperature sensor voltage > 4.864V
Diagnostic Time
10 sec.
MIL ON Condition
3 driving cycle
Temperature [°C(°F)]
Resistance [kO]
-40 (-40)
40.93 ~ 48.35
20 (68)
2.31 ~ 2.57
-30 (-22)
23.43 ~ 27.34
25 (77)
1.90 ~ 2.10
-20 (-4)
13.89 ~ 16.03
30 (86)
1.56 ~ 1.74
-10 (14)
8.50 ~ 9.71
40 (104)
1.08 ~ 1.21
0 (32)
5.38 ~ 6.09
60 (140)
0.54 ~ 0.62
10 (50)
3.48 ~ 3.90
80 (176)
0.29 ~ 0.34