Intake Air Temperature (IAT) Sensor

IAT sensor is an integral part of the charge air pressure sensor. IAT sensor is a Negative Temperature Coefficient (NTC) type. IAT sensor receives a 5 volt reference signal from ECM through a 2.74 kohm resistor integrated in ECM. IAT then returns a varying voltage depending on intake manifold temperature. This sensor is used together with charge air pressure sensor to provide air charge density information to ECM. IAT sensor is used to modify pulse-width modulation of EVAP canister purge valve during changes in manifold vacuum/pressure. IAT sensor is also used to correct ignition timing. If IAT sensor indicates that intake air temperature is lower than 19.4°F (-7°C), ECM will stop specific diagnosing procedure. If IAT sensor indicates that intake air temperature is higher than 41°F (5°C), ECM will start specific diagnosing procedure. If IAT sensor information is faulty, ECM will substitute IAT sensor information with a value of 104°F (40°C).