Using Automobile Code Scanners

Did you just notice the Check Engine Light (CEL) glowing on your instrument panel?  Great, you think. “What’s the problem and how much is it going to cost me to get it fixed?” You might prefer to simply call your local mechanic and schedule an appointment, but these days a lot of people are buying code readers so they can get a little insight into the problem.  Here’s what you should know about these codes readers.

How they work

The fuel injection system, ignition system and many sub-systems on modern cars and trucks are controlled by the main Engine Control Module (ECM). These ECMs collect operating data from the engine and other systems on the car and then send commands that control the ignition coils and fuel injectors. However, as a vehicle ages, things need replacing, or may just out-and-out fail. That’s when the CEL light goes on. It means that the ECM is reading data from some sensor that indicates something is wrong and needs attention. The ECM also stores a diagnostic “trouble code” so a service technician knows what the problem likely is.

Automotive code scan tools are what both professionals and owners use to check ECM codes. Not long ago, these code scanners were really expensive and were really something that professional mechanics used and owned.  Today, however, prices have dropped dramatically. Although you can still buy expensive professional machines, you can also pick up hand-held readers for just $20 or so. The service manager at Westbury Toyota in Westbury, NY, a full-service Toyota dealer, explained to us that the professional scan tools have graphic functions that let a technician monitor several parameters onscreen while the engine is running.  This sort of diagnostic power really isn’t needed by consumers or even most DIYers.

Using a scanner

Using an automotive one is simple, to get started, plug the scan tool into the OBD II connector under the dash.  (If you can’t find the connector, consult the internet or your owner’s manual.)  After you get it connected, turn the vehicle key on then follow the instructions on the scanner’s screen. You’ll get an option to check for trouble codes. There may be several of them, so you may want to write them down.

For interpretation, your code scanner should have a manual or you can find the codes on the internet.  If you are using the internet, type in the model of your car and the code number and you will find dozens of sites that can help you out.

Getting the problem repaired

If your “throws a code” and you find out what the codes refers to, chances are that you will still need a professional mechanic to solve the problem.  Many times the codes refer to the emission systems on your vehicle and these are quite complex today. Plus, there often is some interpretation needed when you analyze codes and professional mechanics perform this on a daily basis.


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