SW2 L4-1.9L DOHC VIN 7 (1997)
Intake Air Temperature: Description and Operation
Temperature - Resistance Chart For Sensors
The intake air temperature sensor is a thermistor-type sensor mounted in the engine inlet air system. A thermistor resists the flow of electricity similar to
a resistor. However, the resistance of a thermistor increases as the temperature drops. For example, at a low air temperature a thermistor produces a high
resistance of 93k ohms at -40°C (-40°F), while a high temperature causes low resistance of 65 ohms at 140°C (248°F).
The intake air temperature sensor is a two-wire sensor that receives a reference signal voltage from the PCM to sensor pin A and a sensor reference
ground from the PCM to sensor pin B.
The PCM supplies the a 5-volt reference signal to the inlet air temperature sensor through a current-limiting resistor located inside the PCM. This signal
is received by the PCM and indicates the temperature of the air entering the engine. This sensor input is used by the PCM for fuel enrichment, ignition
timing, EGR operation, canister purge control, and closed loop fuel control.