http://honda-tech.com/how-tos is the leading Honda Accord and Civic resource for technical DIY guides. There are a few reasons why an alarm may be acting up. For the full step-by-step article, please visit http://www.honda-tech.com/how-tos/a/honda-accord-why-does-my-alarm-keep-going-off-374772
Nobody likes it when their car alarm goes off for no reason. A car that's perfectly safe can attract unwanted attention when the alarm goes off. This video will go over the possible issues with an alarm that goes off for no apparent reason so you can get the alarm working properly again.
Step 1 – Check the Hood Latch Sensor
A common reason for the alarm to continually go off is a bad hood latch connection. The sensor becomes dirty with road grime and engine grease, which creates false positives.
Before unplugging the sensor, you can try to clean it if it looks dirty with grease. People have had luck cleaning it with a brake cleaner spray. After cleaning it, they have reported the issue going away.
To fix a faulty hood latch sensor, open your hood and look down at the latch. Find this wire and push in on the tab that’s on it. This will disconnect the hood sensor and stop the false hood alarm.
Step 2 – Check for a Bad Battery
If the battery is low, then trying to start the car may trigger the alarm. This can be easily fixed by replacing the battery. If the battery is in good shape, try taking it to your local auto parts store and have it tested. If the battery is still in good shape, then there might be a problem with the charging system, or someone may have left a dome light on by accident.
Another battery-related problem could be corroded terminals. Corroded or dirty terminals can cause a poor connection, which forces the car to behave as if the battery is low. If they're dirty, clean them with battery cleaner and a brush.
Step 3 – Check for a Short in the Wiring
If the previous steps have not solved the problem, then you might have a short in the wiring somewhere in the system. If you have an aftermarket alarm, this could very much be the issue. There have been numerous complaints of audio shops doing a poor wiring job during installation. If this is the case, the best bet is to take the car to a reputable stereo and alarm shop, so they can find the short wire.
Now that you’ve gone through the possible causes of your unwarranted alarm activating, you as well as bystanders won’t be disturbed by this nuisance.