Component Location
General Description
The Intake Air Temperature Sensor (IATS) is installed into the Manifold Absolute Pressure sensor (MAP). The IATS uses a thermistor whose resistance changes with the temperature.The electrical resistance of the IATS decreases as the temperature increases, and increases as the temperature decreases. The 5 V power source in the ECM is supplied to the IATS via a resistor in the ECM. That is, the resistor in the ECM and the thermistor in the IATS are connected in series. When the resistance value of the thermistor in IATS changes according to the intake air temperature, the signal voltage also changes. Using this signal, the information of the intake air temperature, the ECM corrects basic fuel injection duration and ignition timing.
DTC Description
ECM sets DTC P0112 if the ECM detects signal voltage higher than the possible range of a properly operating IATS
DTC Detecting Condition
Item | Detecting Condition | Possible cause |
Monitoring Strategy | ? Signal check low | ? Open in signal circuit ? Short to battery in signal circuit(pin 42 to 33) ? Open in ground circuit ? Faulty IATS ? Faulty ECM |
Threshold value | ? Measured temperature : < -38.25?(-36.85?) |
Enable Conditions | ? Idle and no fuel cut-off ? 240 sec after engine start |
Diagnostic Time | ?10.2 sec |
Fail Safe | ? No failurre detected on ECTS - The limp home value of IATS depends on ECTS. ? Failure detected on ECTS - ECM controls with mapping data. |
Specification
| Normal Parameter |
| 20?(68°F) | 40?(104°F) | 80?(176°F) |
Signal Resistance | 2.0 ~ 3.0 ? 3.0 ~ 3.7 V | 0.7 ~ 1.6 ? 2.5 ~ 2.9 V | 0.2 ~ 0.4 ? 1.0 ~ 1.4 V |
Schematic Diagram
Signal Waveform
This figure shows the wave form at terminal 3 of IATS at idle rpm.
The lower the temperature is, the closer the output voltage of IAT goes to 5 V.In case,when engine is warmed up,the output is 5 V.
Possible cause : Open signal and ground line,or sensor’s inner circuit open |
In case,when engine is cold,the output is below 0.5V
Possible cause : Short between signal and groun line Bad ECM |