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

Manifold Air/Fuel Temperature Sensor:

This sensor is located in the intake manifold, and its element is extended into the flow of the incoming air/fuel charge. The purpose of the MAT sensor is to provide input voltage to the ECU. The MAT sensor is a variable resistor, and the amount of voltage that the MAT sensor allows to flow back to the ECU is determined by the temperature of the air/fuel charge. As the temperature of the air/fuel charge changes so does the voltage that returns to the ECU. The ECU uses this information and other input signals to make decisions as to what output devices need to be adjusted to make the driving conditions or emission levels better.

The relationship between the resistance of the MAT sensor and the temperature of the air/fuel charge is inversely proportional (As the temperature increases the resistance of the sensor decreases and vice versa). The relationship between the resistance of the MAT sensor and the voltage returned to the ECU is also inversely proportional (As the resistance increases the voltage returned to the ECU decreases and vice versa).

The ECU provides a 5 volt reference signal to the MAT sensor, and the voltage range of the MAT sensor is .5 to 5 volts. For a chart of temperatures and their relative resistances see SPECIFICATIONS.