Air Temperature Sensor ( Ambient / Intake ): Description and Operation

Airflow Meter:

PURPOSE
Provides ECU with air temperature signal.

LOCATION
Integral component of air flow meter.

OPERATION
The thermosensor is a negative temperature coefficient thermistor; as temperature increases, resistance decreases. Cold air is more dense than warm air. The ECU measures the resistance of the thermosensor, calculates the temperature of the incoming air, and uses this information to help regulate the following:
^ Fuel injection quantity
^ Idle speed control
^ Vapor canister purge control

Sensor resistance is checked at airflow meter terminals "E2" and "THAa":

TEMPERATURE / RESISTANCE (K OHMS)

-4°F (-20°C) / 13.6K - 18.4K
68°F (20°C) / 2.2K - 2.7K
140°F (60°C) / 0.4K - 0.7K