300M V6-3.5L VIN G (2000)
both made of silicone. As the pressures changes the diaphragm moves causing the element to deflect which stresses the silicone. When silicone is
exposed to stress its resistance changes. As manifold vacuum increases, the MAP sensor input voltage decreases proportionally. The sensor also
contains electronics that condition the signal and provide temperature compensation.
The PCM recognizes a decrease in manifold pressure by monitoring a decrease in voltage from the reading stored in the barometric pressure
memory cell. The MAP sensor is a linear sensor; as pressure changes, voltage changes proportionately. The range of voltage output from the
sensor is usually between 4.6 volts at sea level to as low as 0.3 volts at 26 in.Hg (Table 1). Barometric pressure is the pressure exerted by the
atmosphere upon an object. At sea level on a standard day, no storm, barometric pressure is 29.92 in.Hg. For every 100 feet of altitude barometric
pressure drops 0.10 in. Hg. If a storm goes through it can either add, high pressure, or decrease, low pressure, from what should be present for that
altitude. You should make a habit of knowing what the average pressure and corresponding barometric pressure is for your area. Always use the
Diagnostic Test Procedures for MAP sensor testing.
