I have a 2001 Nissan Altima with roughly 53k miles. I changed the battery in my keyless entry remote and since then, my car alarm has been going off at the most random times. It went off while I was driving and I had to pull over on one of the most dangerous stretches of road around! I have the factory system installed and am completely unsure of what the problem is. It seems whenever I have the keys near the car it goes off, but if I don't, it stays silent. This is really aggravating and have never had this problem.
Your alarm is being triggered by the Auxiliary power sounder due to the built in battery failing causing the alarm unit to think that the car is being tampered with. The power sounder unit is located behind the drivers side wheel arch splash guard on the left it is held to the car in a metal housing which is secured by 3 bolts. You can purchase a new power sounder unit or disconnect the unit and tape the connection lead to prevent water ingress if you don't want to pay ?70 for a new unit. Before disconnecting switch on ignition switch off and remove the battery negative lead withing 20 seconds or the alarm will sound. If you choose to remove the power sounder you will still have the default alarm via the main horn if the vehicle is broken into and is sensed by the interior sensors. This can be tested with the drivers side window down then lock the doors there is a indicator lamp in the hazard switch which will be steady on for 1 minute then flashes intermittently. If it flashes fast don't worry after a minute it will slow to tell you the alarm is activated. Once it is flashing steady reach inside the open window alarm will now sound, Unlock car to disable alarm.
Hello First question do you have more than 1 set of keys? If so try leaving the normal one away from the car and use the other set. You may have taken to long whilst changing the batteries. The alarm should never go off whilst you are driving. If you have the manual look up how to match up the key to the alarm system. Check you have the batteries in the right way up. Most new ones use 2 batteries and advise you to only replace one battery then replace the other rather than both out then both new ones in as the memory is lost from the key. Andy C
try disconnecting the black cable on the car battery for a few minutes and see if this just might re set everything to normal.
