SENSOR, Air Temperature, Intake

DESCRIPTION

The 2–wire Intake Manifold Air Temperature (IAT) sensor is installed in the air inlet tube with the sensor element extending into the air stream.

The IAT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as inlet air temperatures increase, 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 inlet air 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

1. Disconnect and isolate the negative battery cable.

 
2. Remove the engine cover (1).
   
   

 
3. Disconnect the electrical connector (1) from the inlet air temperature (IAT) sensor.
   
   

 
4. Clean dirt from the air inlet tube at the IAT sensor base.

 
5. Gently lift the small plastic release tab (3), rotate the sensor about 1/4 turn counter-clockwise and remove the sensor from the inlet air hose.

 
6. The IAT sensor O-ring (2) can be reused if not damaged.
   

 

INSTALLATION

1. The sensor mounted O-ring seal (2) can be reused if not damaged.

 
2. Clean the IAT sensor mounting hole in the air inlet hose.

 
3. Install the IAT sensor into the air inlet hose and rotate clockwise until the release tab (3) engages.
   
   

 
4. Install the electrical connector (1) to the IAT sensor.
   
   

 
5. Install the engine cover (1).

 
6. Connect the negative battery cable and tighten nut to 5 N·m (45 in. lbs.).