2001 Honda Civic, key green light keep flashing and the car wont start

did you replace the switch or ignition lock cylinder, if you just replaced the switch ,and you disconnected battery you must have the original key to start it because it thinks someone trying to steal vehicles there a green key on dash that comes on then stays on, or goes out.if light stays on then the problem is the emoblilzer.you may have to have it towed to a dealer to have it reprogrammed.good luck, mike

The flashing green key icon when turning off your car? Ignition security system, requires chipped key to start. It's sort of like the GM and Ford flashing red light to announce the security system is active.

Check the manual for flashing key.You can also google the question and go to a Civic forum

either the key you are using is without a chip,or lost the program or the immobilizer is activated,

Car not starting or turning over indicates towards multiple possibilities. It can be issue with battery or weak battery. But if battery checks out ok, then it can be starter issue or faulty alternator or problem with low fuel pressure or no spark at spark plugs due to dirty spark plugs or faulty ignition coil or injectors getting cracked or dirty and needs to be cleaned.

To confirm the problem, the basic troubleshooting is required.

Click this link below and follow the troubleshooting:------

http://technoanswers.blogspot.in/2012/02/car-starting-issues.html

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This will help.

Thanks.

Hi,

Actually I need more detail about your honda civic. I your green key light flashed and the will not start. the problem is usually on fuel pump for honda civic 1999- 2003. What year is your car?.
To make your car enable running, just turn on your key ( BUT don not start) , wait for moment until your fuel is primed and light goes Off, then start your car. It should be work.

Regards

If it were the immobilizer, you would have a security light that would be flashing or staying on all the time the key is in on. Since the engine cranks over and the pump is working when you turn the key to on and start, the green light may just mean the bulb is burnt out or a connection problem with that wire for the light. Not much of a problem there.
You said no fuel or fire when trying to start-so that is where to concentrate: you first need to verify that the ignition still is working, so check for spark on a plug wire with the engine cranking over. This could be a main fuse or main relay not passing power on to the ignition system and/or the injector circuit. First check for spark, and if you have spark, check the injector circuit (there is a fuse for the injectors-probably under the hood in a fuse/relay block). If you have no spark, you will have to diagnose the ignition system- coils, ignition control module (the ignitor), the crank angle or crank position sensor, finally the engine computer.

If there are absolutely no problems of any kind, it may simply be a reminder to remove your key. There's a transponder chip inside the key and it is designed to not allow you to lock your keys in the car. Do you only see the flashing green light when you are stopped and your key is in the ignition?

This is a tricky area to diagnose, if there are any other issues. Have you had any indication of intermittent power, due to your ignition switch? Sometimes, weight from additional keys and from the fob can cause wear in the ignition switch, which can lead to these problems. Also, the main relay may be failing, which provides power to the immobilizer. If you can rule out a problem with the ignition switch, I would try replacing the main relay. Be sure to disconnect the negative battery cable first, after recording any radio codes.

My bet is that it's a reminder to not forget your keys. Check your Owner's Manual.

I hope helps (remember to rate this answer).

first of all recharge the battery

check u r alarm system