Circuit Description

The mass air flow (MAF) and the intake air temperature (IAT) sensor 1 are an integrated sensor. The IAT sensor 1 is a variable resistor that measures the temperature of the air entering the induction system. The powertrain control module (PCM) supplies 5 volts to the IAT sensor 1 signal circuit and a ground for the IAT sensor 1 low reference circuit. When the sensor is cold, the resistance is greater. This results in a greater voltage on the signal circuit that is interpreted by the PCM as a colder IAT. As the sensor becomes warmer, the resistance decreases. This results in a lesser voltage on the IAT signal circuit that is interpreted by the PCM as a warmer IAT. If the PCM detects an IAT sensor 1 signal voltage that is not within a calibrated range of the IAT sensor 2 signal voltage, DTC P0111 sets.