The manifold absolute pressure (MAP) sensor responds to changes in
intake manifold pressure (vacuum). The MAP sensor signal voltage to the
PCM varies from less than 2.0 volts at idle to more than 4.0 volts with the
key ON and the engine OFF, or at wide open throttle (low vacuum).

The MAP sensor is used to determine engine vacuum level for other
diagnostics, to determine the barometric pressure (BARO) and to
determine any manifold pressure changes while the linear EGR flow test
diagnostic is being run.
Manifold Absolute Pressure sensor   ( MAP )
Warning Lights