It used to be easy to reset and turn off the check engine light. For vehicles manufactured and sold prior to 1996, there are a few cheap and easy fixes. One popular fix is to disconnect the negative terminal on the battery and turn on the headlights for ten to fifteen minutes. Draining the power in the car's capacitor will also reset the computer and turn off the check engine light.
This may be popular but it's not really a good idea. For one thing, it will clear the presets on your car radio, clock and anti-theft devices. It will also clear the performance memory from the car's computer, which it will have to "re-learn" over the next forty or so driving trips. You will suffer both poorer driving performance and lose gas mileage while it does so.
A similar cheap and easy fix is to find and pull the fuse to the ECU (Engine Control Unit). This has the same disadvantages as disconnecting the battery.
A better idea - especially for cars sold in the U.S. from 1996 to the present - is to read the owner's manual. In some cases the manual will tell you how to reset the check engine light, usually through a series of prescribed pedal pressing and button pushing and so on.
Most often, however, the manual will give you the sage advice to take your vehicle to an authorized dealer.
You can take your car to the dealer where they will check its computer for trouble codes and reset the check engine light. On some occasions it may be a minor problem such as a loose gas cap, though it certainly could be something more serious. In any case taking your vehicle to the dealer for a check engine light will not be cheap.
Another way to turn off the check engine light is to simply wait it out.
One of the best ideas is to invest in a diagnostic tool or scanner. Such a tool connects easily to your car's computer through an input under the dash near your knee. The scanner retrieves the computer's trouble codes that help diagnose the problem. It will also reset and turn off the check engine light without clearing everything else in your car's computer.
Another nice thing about the better scanners is their ability to indicate your vehicle's state emissions status - whether you are likely to pass or fail the emissions test.
Once you you have turned off the check engine light, it is a good idea to drive your vehicle for a good fifteen minutes or so - and at highway speeds if possible. If the light comes back on, it may mean a real problem that should be checked by an ASE-certified technician.
To learn more about saving time and money with a diagnostic scanner, click on the link below.