Making Sense of Sensors: Part 2

The computer does a lot more than these basic functions I've mentioned here. It sends signals to control transmission shift timing, cruise control and other things. All I have attempted to do here is give you a basic understanding of how the inputs, the computer and outputs relate to each other.

It is important to keep in mind that when a trouble code indicates a component has failed, it does not necessarily mean that it is indeed the component itself. You still need to check the whole circuit to find out if it is a bad part or bad wiring. The most common part to be replaced needlessly is the O2 sensor. When a sensor goes out of range and sends bad information to the computer, the O2 sensor will try to compensate for it. This often results in a malfunctioning O2 sensor code. In cars with early self-diagnostics and OBD I, this was easy to do. With OBD II it has become a little more difficult to fault a good O2 sensor since the OBD II codes are more specific.

© 2001 - 2004 Vincent T. Ciulla