The computer in your Mitsubishi Montero controls the air to fuel ratio and emissions control system. If there is something wrong with any of the various sensors on the Montero, the module, called an ECU, will generate a trouble code. You can get a free diagnostic scan at most auto parts stores. However, a more precise scan can be done at a Mitsubishi dealership. Once you’ve discovered the problem and fixed it, you need to know how to reset the computer on your Montero.
Pull down the fuse panel cover of your Montero. The fuse panel is located in the driver side footwell, under the steering column.