Theory Of Operation

The Intake Air Temperature Sensor and Manifold Absolute Pressure Sensor are combined into one component (TMAP). The 5 volt supply circuit is only used for the pressure sensor portion of the TMAP which operates like a typical three wire MAP Sensor. The integrated temperature sensor portion shares the common sensor ground circuit with the pressure sensor. The internal pressure sensor and temp sensor each supply feedback to the PCM through dedicated signal circuits.

The MAP Sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. With the ignition on and the engine not running, the MAP Sensor provides the PCM with the Barometric Pressure (BARO) reading. When the engine is running, the MAP Sensor signal supplies the PCM with the current air pressure within the Intake Manifold.

The IAT Sensor signal supplies the PCM with the temperature of the air entering the Intake Manifold. This information is used by the PCM, along with other inputs to calculate fuel delivery, and timing needs.