Your Check Engine Light (CEL) just popped on. Great, you say to yourself, what does that mean? You have two ways to answer that question: you can go to a mechanic, have them read the code and professionally diagnosis the results or you can do it yourself with a code reader. Considering trying it yourself? Here’s what to know:
The fuel injection, ignition system and automatic transmission on most modern cars and trucks are run by computers. These computers collect operating data from the engine and other systems on the car and then send commands to the ignition coils, fuel injectors and other systems. They also store a great deal of this operating data in memory so mechanics can get insight into what’s been going on when service is needed.
When the CEL light does goes on, it means that one of the computers (for example: the Powertrain Control Module or PCM) is receiving data from some sensor that indicates something isn’t working right. The PCM also stores a diagnostic “trouble code” so a service technician knows where to look for the problem.
Code scan tools are what both professionals like the service folks at Four Seasons Ford use, and what regular owners can use to check PCM codes. Not long ago code scanners were expensive. They were really just for service technicians. Today, prices vary from $20 or so for a simple code reader to maybe $400 for full-featured machine. The inexpensive ones lack the fancy features of the high-end ones but they are quite useful, nonetheless. Consider getting one.
Using a code scan tool is simple. To get started, plug the scan tool into the OBD II connector under the dash of your car. (If you can’t find the connector, consult the internet or your owner’s manual.) After you get it connected, turn the car’s key on then follow the scan tool’s onscreen instructions. Eventually you’ll get an option to check for trouble codes. You may want to write then down if you see any.
For interpretation, the manual that came with the scan tool may help or go online. On Google, type in the model of your car and the code number that the scan tool displayed and you will find dozens of sites that can help you diagnose what the problem is. Your ultimate resource, of course, is to have your local dealer take a look at your car, though.