Theory Of Operation
WARNING: This page is about a different car, the 2016 Dodge Durango. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) uses the MAP Sensor base model and the Electronic Throttle Control (ETC) Motor position value to create a calculated MAP model value. This calculated MAP model is then compared to the actual MAP Sensor Signal input to the PCM. The PCM uses this comparison to detect vacuum leaks or restrictions in the intake air system. The purpose of this monitor is to detect an instantaneous or gradual change in the intake manifold vacuum that exceeds the calibrated high or low thresholds.
NOTE:
Do not use shop air to clean out the MAP Sensor when diagnosing a MAP Sensor related fault as this will cause internal damage to the sensor.