The Manifold Absolute Pressure (MAP) provides instantaneous information about manifold pressure to the Powertrain Control Module (PCM), which uses this data to calculate the air density and thus determine the mass / air flow rate of the engine. In the same way, the dosage of the necessary fuel is determined so that there is an optimum combustion.
The Powertrain Control Module (PCM) compares the signal of other sensors with respect to that of the Manifold Absolute Pressure sensor (MAP), in order to check that it is working correctly. For example, compare the signal from the throttle position sensor (TPS) with that of the Manifold Absolute Pressure sensor (MAP) so that the signal from the latter sensor is not fixed.
In the event that the Powertrain Control Module (PCM) does not observe a change in the MAP sensor, a change in the TPS sensor occurs and the diagnostic code P0105 is established.