Circuit Description

MAP sensor changes resistance based upon manifold vacuum. PCM provides a 5-volt reference and ground signal. MAP sensor signal varies between ground and 5 volts as manifold vacuum varies. As MAP decreases, voltage decreases (low engine load, high vacuum). As MAP increases, voltage increases (high engine load, low vacuum). PCM uses MAP sensor value as an indicator of engine load.

This test monitors the MAP signal by comparing the reading to calculated BARO. If the values of the MAP signal and the calculated BARO are too close together at idle, DTC will set.