SENSOR-INTAKE AIR TEMPERATURE
DESCRIPTION
The 2–wire Intake Manifold Air Temperature (IAT) sensor is installed in the intake manifold with the sensor element extending into the air stream.
The IAT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as intake manifold temperature increases, resistance (voltage) in the sensor decreases. As temperature decreases, resistance (voltage) in the sensor increases.
OPERATION
The IAT sensor provides an input voltage to the Powertrain Control Module (PCM) indicating the density of the air entering the intake manifold based upon intake manifold temperature. At key-on, a 5–volt power circuit is supplied to the sensor from the PCM. The sensor is grounded at the PCM through a low-noise, sensor-return circuit.
The PCM uses this input to calculate the following:
- Injector pulse-width
- Adjustment of spark timing (to help prevent spark knock with high intake manifold air-charge temperatures)
The resistance values of the IAT sensor is the same as for the Engine Coolant Temperature (ECT) sensor.
REMOVAL
The intake manifold air temperature (IAT) sensor (1) is installed into the left side of intake manifold plenum .
1. Disconnect electrical connector (3) from IAT sensor.
2. Clean dirt from intake manifold at sensor base.
3. Gently lift on small plastic release tab (2) or and rotate sensor about 1/4 turn counter-clockwise for removal.
4. Check condition of sensor O-ring.
INSTALLATION
The intake manifold air temperature (IAT) sensor (1) is installed into the left side of intake manifold plenum .
1. Check condition of sensor O-ring.
2. Clean sensor mounting hole in intake manifold.
3. Position sensor into intake manifold and rotate clockwise until past release tab (2).
4. Install electrical connector (3).