ECM DTC EO31: Shorted Map Sensor Circuit: Description

The manifold absolute pressure sensor (MAP) is a sensor that changes resistance based upon manifold vacuum. The ECM provides a 5 volt reference and ground. The MAP 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). The ECM uses MAP sensor values as an indicator of engine load. Code EO31 sets when the ECM detects a MAP sensor signal that is too high. The MAP sensor connector is located on the rear top of engine.