General Information

Component Location





General Description

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).

DTC Description

Checking output signals of IATS under detecting condition, if an output signal is intermittently below 0.1V, PCM sets P1112.

DTC Detecting Condition





Specification





Schematic Diagram





Signal Waveform




The output signals of IATS & ECTS change smoothly without any rapid changes. Those have almost same characteristic signal during the early period after start. It means that the temperatures of intake air and engine coolant are depended on the temperature of atmosphere. Meanwhile, during the warming up, the output signal of ECTS is going up increasingly, But, the output signal of IATS changes a little bit. Even it may not change almost. It means that the heat of engine does not affect on the temperature of intake air.