2003 honda civic engine light?

the condition that is causing the light to come on is intermittant. the check engine light means that there is a condition that the engine management system has detected that could cause the vehicle to emit excessive emissions. There are over 150 conditions that can cause the check engine light to come on.

The way the self-test that turns on the check engine light works is that it tests all of the engine management systems when the test conditions are met. if a system or component fails two consecutive tests then the check engine light comes on. Then, if at any time after that the problem is not present on two consecutive self-tests the check engine light is turned off. when the problem is again present and it fails two tests again, the light comes back on. so your problem is intermittent meaning sometimes its there, sometimes its not.

it would be silly to try and guess which of the tests is being failed. However, each time the light comes on a code is stored to tell a techincian which problem was detected. you can find out the stored diagnostic trouble code by taking the car to any Autozone parts store and they will download the code for free. AAMCO transmissions also advertises that they will do it for free but then they may want to sell you a diagnosis once they download the code. many shops will pull the code at no charge. once you have the code you can put a post out to find out what it means if the shop or store can't tell you.

lastly, the one thing you do want to check is to make sure your gas cap is on tight. that is one thing that will cause the check engine light to come on intermittently. make sure the gas cap clicks three times when you tighten it. otherwise the system will detect that its leaking and put the light on.

hope that helps

2003 Honda Civic Si Engine

I would have to say that it could be something simple as the gas cap not tightened properly or there is some debris on the inner gasket seal in side the gas cap. Rub the seal off and make sure when you tighten it that you hear 3 clicks. If it does not click properly the cap might be bad. Try it again and then let the car be turned off and the on again the next day. It may go off then or it may go off when driving after the second start when you are driving. This has happen to me 2 times. Once about six months ago and then recently. I would bet that the cap is either going or is not sealing properly. This is the first thing I would do before spending money on a new cap or a service,

Sometimes, a loosen or broken wire causing the check engine light by different reading value then standard, and sometime the tank cap seal is worn even the 'clicks' is already finded. The 50 mph is because the computer set the engine to run in default mode to avoid another major problem to the Civic. My suggest, please do check to all sensor wire, repair as necessary.

I cant tell just by the light coming on, you should go to an autoshop and they'll hook your engine up to a computer and your engine will tell them what is wrong, its usually free to a couple of bucks

get it diagnosed at auto zone

get it scanned at auto zone