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 5V 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, ignition timing correction and idle speed correction(Air-density correction).
Checking output signals of IATS every 120 sec. under detecting condition, if an ouput signal is over 4.9V for more than 4 sec., PCM sets P1111.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● This code detects a continuous short to high in either the signal circuit or the sensor | ● Poor Connection ● Open or short in signal circuit ● Open in ground circuit ● Faulty IATS ● Faulty PCM |
Enable Conditions | Case 1 | ● No VSS Fault Active (No P0501) ● No Coolant Short Active Fault Present ● No MAF Active Fault Present ● Engine Air Flow < 15 g/s ● Vehicle Speed < 25kph ● Engine Coolant Temperature > 50°C( 122 °F) ● Engine Running Time > 120 sec. |
Case 2 | ● No VSS Fault Active (No P0501) ● No Coolant Short Active Fault Present ● No MAF Active Fault Present ● Engine Air Flow < 15 g/s ● Vehicle Speed < 25kph ● Ignition off time > 360 min. ● Engine Coolant Temperature > -10°C( 14 °F) ● Engine Running | |
Threshold value | ● IATS signal > 4.9V | |
Diagnosis Time | ● Continuous (More than 4 sec. failure for every 120 sec. test) | |
MIL On Condition | ● DTC only (NO MIL ON) |
Temp. (°C/°F) | Resistance (kΩ) | Temp. (°C/°F) | Resistance (kΩ) |
-40(-40) | 95.95 ~ 105.78 | 20(68) | 3.42 ~ 3.61 |
-20(-4) | 27.4 ~ 29.77 | 40(104) | 1.43 ~ 1.5 |
0(32) | 9.08 ~ 9.72 | 60(140) | 0.66 ~ 0.69 |
10(50) | 5.49 ~ 5.83 | 80(176) | 0.33 ~ 0.34 |
