TROUBLESHOOTING FOR DTC
DTC | P1140 | Intake Air Temperature Sensor (IATS) Circuit Malfunction |
CC-CODE | 0b | Signal low (Open circuit or short circuit to battery line) |
02 | Signal high (Short circuit to ground) |
The intake air temperature sensor (IATS) is built in the mass air flowmeter sensor (MAFS). It is located between the air cleaner assembly and the throttle device. The IATS uses a thermistor whose resistance changes with the temperature to check the mass of intake air entering the engine.
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 fuel flow, injection timing.
DTC DETECTING CONDITIONCC-CODE | Detecting Condition | Suspect Area |
0b | Intake air temperature < -49°C(-56.2°F)
| Open or short in IATS cirucit IATS ECM
|
02 | Intake air temperature > 130°C(266°F)
|
SPECIFICATIONTemperature [°C (°F)] | -40(-40) | -20(-4) | 0(32) | 20(68) | 40(104) | 60(140) | 80(176) |
Resistance (kO) | 39.3 | 13.9 | 5.5 | 2.4 | 1.2 | 0.6 | 0.3 |
[SCHEMATIC DIAGRAM]
INSPECTION PROCEDURE