Code P031, Shorted Manifold Absolute Pressure (Map) Sensor: Notes

MAP sensor changes resistance based upon manifold vacuum. PCM provides a 5-volt reference and ground. MAP sensor signal varies between ground and 5 volts as manifold vacuum changes. As MAP decreases, voltage decreases (low engine load, high vacuum). As MAP increases, voltage increases (high engine load, low vacuum). PCM uses MAP sensor values to indicate engine load. Code P031 sets when PCM detects a MAP sensor signal that is too high.