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 higher than the maximum threshold value during 2sec, ECM sets DTC P0112.(In this case, the input signal voltage is the minimum threshold vaue.)
Item
Detecting Condition
Possible Cause
DTC Strategy
Signal check, low
Poor connection
Short to ground in signal circuit
IATS
Enable Conditions
-
Threshold Value
Measured temperature > 128.3 ?
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