The Intake Air Temperature Sensor (IATS) is installed into the Mass Air Flow Sensor (MAFS). 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.
ECM sets DTC P0113 if the ECM detects signal voltage higher than the possible range of a properly operating IATS.
Item
Detecting Condition
Possible Cause
DTC Strategy
Voltage range check
Short to battery in signal harness
Open in signal or ground circuit
Contact resistance in connections
Faulty IAT sensor
Enable Conditions
6 < Battery voltage
Time after start > 110 sec.
Threshold Value
Measured intake air temperature < -46?(-51?)
Diagnostic Time
5 seconds
Fail-Safe
No failure detected on ECTS
- The limp home value of IATS depends on engine coolant temperature.
Failure detected on ECTS
- PCM controls with mapping data.
Mil On Condition
2 Driving Cycles
Temp.(°C)
Temp.(°F)
Resistance(kO)
-10
14
8.5~9.7
20
68
2.3~2.5
0
32
5.4~6.1
30
86
1.6~1.7
10
50
3.5~3.9
80
176
Approx. 0.3
Fig 1,2) Signal decreases with increasing sensor temperature and increases with decreasing sensor temperature : Approx. 3769mV at 19.5?(at IG ON), Approx. 3574mV at 24.0?(at Idle)
Fig 3) Open or short to battery in signal circuit/Open in ground circuit : Approx. 5V
Fig 4) Short to ground in signal circuit : Approx. 0V