Theory Of Operation
WARNING: This page is about a different car, the 2015 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) rationalizes the intake manifold pressure by comparing the Boost Pressure Sensor input to the Barometric Pressure Sensor input. The Barometric Pressure Sensor is located internal to the PCM. The Boost Pressure Sensor is mounted on the Intake Manifold. It is sometimes called the 'TMAP'. This test runs at initial key on/prior to engine start, again after the engine is shutdown, and during after-run mode to determine the plausibility of these Sensors.