Pcm Code E31, Shorted Map Sensor Circuit: Description

The MAP sensor output signal voltage is a DC voltage that varies with manifold absolute pressure. As MAP decreases, voltage decreases (low engine load, high vacuum). As MAP increases, voltage increases (high engine load, low vacuum).

The PCM uses MAP sensor values as an indicator of engine load. A high MAP reading indicates heavy load, and low MAP reading indicates low load. Code E31 is designed to set when PCM detects a MAP sensor signal out of high side limit, or also with MAP signal at 4.85 volts or more, and having a value greater than 108 kPa.