Manifold Absolute Pressure (MAP) sensor

MAP sensors operate by intake manifold pressure or vacuum acting on a diaphragm inside the sensor. As the pressure changes, the diaphragm alters the resistance of the variable resistor which in turn changes the signal back to the ECU.
After doing the tests, We were able to plot 2 graphs. One of Vacuum vs. Pressure Intake Manifold (PIM) voltage, and another of Vacuum vs. voltage drop.
From the results, and the graph trends, we were able to see that as vacuum increases, the PIM voltage (signal voltage) decreased. We can also see that as vacuum increases, voltage drop increases. What this means is that as vacuum increases, the voltage back to the ECU decreases.
Note: MAP sensors only use 5 volts.