Barometric Pressure Switch: Description and Operation

MAP/BARO Solenoid:

MAP/BARO Solenoid
The MAP/BARO solenoid (Figure 11) switches air flow passage between manifold vacuum and atmospheric pressure upon demand from the PCM. When voltage is supplied from the PCM, the MAP/BARO solenoid turns "ON". When "ON" the MAP/BARO sensor monitors barometric pressure (BARO); when the MAP/BARO solenoid is "OFF" Manifold Vacuum Is Monitored (MAP).