2006 elantra anti-theft issue
 

I am storing a 2006 Elantra for a friend. Recently I let it run for awhile to keep the battery charged. I unlocked it with the key since the fob doesn’t work. My husband is the one who shut if off, and he tried to lock it using the fob. Then when he saw that doesn’t work he locked it with the key. Later we noticed the alarm was going off, cycling thought being on, then off, then on, then off again. We couldn’t get it to stop since the fob doesn’t work, so we disconnected the battery. A few days later I reconnected the battery. The alarm didn’t start going until after I started the car. The hazard lights and several warning lights also flashing during each cycle when the alarm is on. I think we triggered the anti-theft alarm and we can’t turn it off. I’ve tried all the methods I found in the forum to reset the alarm - including turning the key in the ignition to on and leaving it there for 30 seconds or longer, and also turning it in the door and holding it there for 30 seconds. Nothing helps. Also the car now takes 2 tries to start. Any ideas? I don’t want to have to go to the dealer and/or get a new fob - friend wants to sell the car without spending more on it.