How do you reset the check engine light on a 1999 Honda Accord?

Most check engine lights can be reset if you know the pinout on the diagnostic plug by doing a simple jumping of terminals . To find out which terminals are involved consult a repair manual or if you have an Advance Auto Parts store nearby they can hook up the diagnostic computer and reset the check engine light. One other industry standard is to disconnect the battery , and then reconnect it . You may have to leave it disconnected for 20 minutes or so to reset the light, Again check a service manual- the library is a good place to find one without having to buy one(they are expensive) . Motors or Chiltons are usually pretty good quality and informative. The reset procedure is usually in there but may take a bit of searching to find . Hope this helps Use an OBD (On Board Diagnostic) scanner to find out what's wrong. Fix the problem then the light should go off. It's often an oxygen sensor or something equally trivial. By taking it to a professional and have the problem that the computer has detected repaired. pull the "Backup/ACC" fuse from the main panel under the hood. Wait 15-30 secs and replace it. However, this will reset all of your accessories as well and you will need to re-enter your security code on the radio to get it to work. Pull the codes from the computer, match the code to the troubleshooting procedure, follow the procedure to find the source. Repair the source, light will go out if that was the only problem. There are "monitors" or self tests the computer runs the car through a drive cycle, if a problem occurs, it may not run all of the self tests until that problem is taken care. Therefore, another problem may exist. It is emission related. OR hook up a scanner that is capable of clearing codes, and hope that none are still active. The " check engine light" is by far one of the most misunderstood technological advances by the public. I am sure I will revise this as time goes on, as it is an in-depth understanding for the public. It is a warning light that is illuminated when there is a problem with the EMISSION SYSTEM only. Emission system being the pollution control system. Don't get a hard on against it as it is a good thing once you understand it. One point that was brought up a a recent meeting of technicians was that the amount of hydrocarbons is greater when the gas cap is left off than when the engine is running. Hydrocarbons are part of pollution emitted as gasoline evaporates. Going a step farther, one facet of the emission system is the "Evaporative" portion. This is when the fumes from the gasoline are leaking from the system into the outside air. This is one part of the emission system that can trigger a check engine light. I would say that about 7% of the vehicles that have a check engine light are the result of a loose or inadequate gas cap. But understand that many scenariOS are possible with the "check engine light" The vehicle's powertrain computer (note that some vehicles have 17 different computers) will run a series of self-tests. They will only run under certain criteria. And they can be vastly different from manufacturer to manufacturer. Some self-tests are not run until preceding ones have run successfully. So if there is a problem in one particular area that is preventing another self test from running, you can have a situation where one problem is fixed, but another still exists. If you fix a problem and drive the car through a drive cycle that sets the monitor (or self test) the light will go off as it passes that criteria that triggered it in the first place. After 1996, the auto industry went to a idea called OBD II (on board diagnostics). This was to get all the manufacturers onto a similar plane for troubleshooting and powertrain control. While they still differ vastly, many corrections and adaptations were made for technicians to better fix the check engine light problems. Prior to this there were so many different and poor troubleshooting data from a check engine light problem that resolving the problem was much more difficult. Many early warning light of this nature were set to illuminate based on mileage. An Oxygen sensor was one of the things that were meant to be replaced when that mileage was hit. This is much like many current "Change oil lights