Grand AM L4-144 2.4L DOHC VIN T SFI (1997)
Intake Air Temperature Sensor: Description and Operation
Description
The Intake Air Temperature (IAT) sensor is a thermistor (a resistor which changes value based on the temperature of air entering the engine), similar to
the engine coolant temperature sensor. Low temperature produces a high resistance (100,000 ohms at -40°C / -40°F) while high temperature causes low
resistance (70 ohms at 130°C / 266°F).
Operation
The PCM supplies a 5 volt signal to the IAT sensor through a resistor in the PCM and monitors the terminal voltage. The voltage will be high when the
intake air is cold, and low when the intake air is hot. By measuring the voltage, the PCM knows the intake air temperature. This input is used in starting
and running fuel control calculations.
Circuit Faults
A fault in the IAT sensor circuit should set either a DTC P0112 or DTC P0113.
