The Intake Air Temperature (IAT) sensor determines the air temperature inside the intake manifold. Resistance changes in response to the ambient air temperature. The sensor has a negative temperature coefficient. As the temperature of the sensor rises, the resistance across the sensor decreases. This provides a signal to the PCM indicating the temperature of the incoming air charge. This sensor helps the PCM to determine spark timing and air/fuel ratio. Information from this sensor is added to the pressure sensor information to calculate the air mass being sent to the cylinders. The IAT is a two wire sensor, a 5-volt reference signal is sent to the sensor and the signal return is based upon the change in the measured resistance due to temperature.
- Turn the ignition switch OFF.
- Disconnect the wiring harness from the IAT sensor.
- Measure the resistance between the sensor terminals.
- Compare the resistance reading with the accompanying chart.
- If the resistance is not within specification, the IAT may be faulty.
- Connect the wiring harness to the sensor.