Breeze L4-2.4L VIN X (2000)
The MAP sensor signal is provided from a single piezoresistive element located in the center of a diaphragm. The element and diaphragm are 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 rang 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 go through it can either add, high pressure, or decrease low pressure, from what should be present for the 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.
