Making Sense of Sensors: Part 1

   Now not all engines have all of these sensors. And there are other inputs other then the ones I've described here. The ECU gets input signals from the A/T Control unit, Ignition Switch and Air Conditioning Switch.

   The ones I have listed here are the most directly responsible for proper fuel management. If you have a drivability problem, rough idle or starting problem, these are the most likely to be the cause. Understanding them will go a long way in helping you figure out what's wrong with your car.

   While these sensors can, and do, go bad it's important to always check the basics before condemning a sensor. You have to look at the connectors and make sure they are clean and tight. A loose or dirty connector can cause the same symptoms as a bad sensor. Check the wiring as well. Make sure there are no broken or chafed wires. Make sure any vacuum lines that may be connected to a sensor are in good shape. In short, check everything else before you check the sensors. About 75% of the time it is not a bad sensor, just a bad connection.

   Well, that just about covers the inputs. Next time we'll discuss what happens when the ECU digests this information and what outputs it controls.

   Copyright © 2001 - 2003 Vincent T. Ciulla All Rights Reserved