Sensory Overload and Your Car

By Luigi Fraschini

If you're lucky, you have five operating senses. You are able to hear, smell, taste, touch and see. If you're psychic or you see dead people, you might have at least one more. Your car might not have five senses, but the senses that it does have, because of its modern technology, are extremely important. If those senses in the form of its sensors fail, you could well be stranded by the side of the road. Because of their sophistication, today's vehicles diagnose and address changes by themselves using computer technology. While the technological advancements that engines and other systems have experienced offer many benefits, the sensors must be maintained and checked regularly so that the vehicle can get maximum fuel economy and so that everything stays running smoothly.

In other words, "Pay attention to your 'check engine' light and your vehicle's sensors or you could pay the price," said Bryan Gregory Advance Auto Parts' director of consumer education. "Sensors monitor air-fuel mixture, engine temperature, air-flow, wheel speed and more, so essentially they are telling your vehicle's computer what to do. If your sensors fail, your engine may experience poor mileage and performance, and in severe cases, your engine may fail altogether."

We're pretty sure you won't like that. The good news is in most cases, a "check engine" light will illuminate to let you know that there is a problem. Many auto service technicians and retailers like Advance Auto Parts will scan your On-Board Diagnostic (OBD) port at no charge and print out the fault code to help you determine your next steps.

Unfortunately, the next steps are not all that easy for a backyard mechanic.  Access to the sensors is usually the most difficult part of the replacement process. In the case of oxygen sensors, the project can be simplified by using a specially designed O₂ sensor socket that accommodates the sensor wiring. A Haynes Repair Manual specific to your vehicle can be very helpful when replacing sensors as well. It is recommended that if you are a novice at sensor replacement, gain a thorough knowledge of what you need to do and how you need to do it before you try to attempt changes. Advance Auto Parts offers a "Sensors 101" clinic on its Web site that can help you gain a better understanding of what is involved.

A good first step is to know the difference between the two types of indicator lights you are likely to see on your dashboard. "Warning Lamps," sometimes referred to quaintly as "Idiot Lights," most often deliver information about a suspected negative situation having to do with a single component, things like low oil pressure or excessive engine coolant temperature, for example.  "Malfunction Indicator Lights" (MILs), on the other hand, are tied to multiple systems. They generally provide warning that something is potentially amiss, but they don't give much of a clue as to what that is. MILs most often require a technician to download "fault codes" from the on-board computer as the first step to a fix.

The important takeaway is this: If a MIL comes on, pay attention to it and have it checked out by a competent technician. It might seem as if your car is still running properly, but there could be a key malfunction in the engine that might leave you stranded and your car, your life . . . basically everything. 

Cleveland-based Driving Today Contributing Editor Luigi Fraschini writes often about car maintenance issues, which, he says, is easier than actually fixing cars.

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