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/PCM. The ECM/PCM applies 5V to the IAT sensor. The ECM/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 ECM/PCM will receive a high voltage input, and when the air temperature is warm the ECM/PCM 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 input signal voltage of IATS is lower than the miminum threshold value during 2sec, ECM/PCM sets DTC P0112.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Signal check, low | 1. Poor connection 2. Short to ground in signal circuit 3. IATS |
Enable Conditions |
•
Time elapsed after start > 2 sec | |
Threshold Value |
•
Input signal voltage of IATS < 0.132V | |
Diagnostic Time |
•
2 sec | |
MIL ON Condition |
•
3 driving cycle |
Temperature [°C (°F)] | Resistance [kΩ] |
-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 |
