Alarm Randomly Sounds

[BriLevine]

I have a 2007 G35x Infinity. This past March 2011, the alarm randomly started to sound, soemtimes in the middle of the night, every few hours, sometimes during the day. This has happened to me at home and at work. I took it to the dealer initially and they found fault codes B2617, B2553, B2562 & P1815. They cleared them and told me that should do the trick, as the codes were too random to tell them anything. One week later, more alarms. This time I left the car with them for two weeks and they could not replicate the issue. I took the car back, and the next day another alarm. I sent it back for another ten days, they couldnt replicate. I have the car now and I have stuffed acoustic foam in the horns, so that when it goes off, it wont wake up my neighborhood, but this time I wont have to pull the fuse out which means when I take it to the dealer, hopefully they can pull some sort of error code. I have had my keys checked, the dealer left the car inside, outside, wet, dry and nothing. It is a factory car alarm, and nothing on the car has been modified. 22k miles.

Been two months of hell and I see no resolution in sight. Any help or advice is greatly appreciated.

[SteveTheTech]

That sounds like a really crappy wake up call.

If it has not happened for the dealer, I wonder if something in the environment around the car is triggering a false signal.

Where do you park the car?
What's it near?

[BriLevine]

It's been parked in the same spot since November when I moved to my current home, and the problem didnt start until March. It is right in front of my door with my wife's car to the right and my neighbors car to the left. The two of them have also had the same car since before I had this one. It is under a tree, but nothing out of the ordinary. I tried to think about what sort of things changed, wirelss devices etc, but nothing is new in my home. I imagine it could potentially be some frequency triggered by soemthing one of my neighbors has, but since it happens at all hours of the night, I question what kind of device it could be. Very stumped!

[SteveTheTech]

That is exactly what I was thinking.

Why is it only at night...
For years these types of issues have driven me nuts. The owner is desperate by the time I usually meet them.

Do any of the cars you park next to have keyless go or iKey type systems.

As one of the attempts, had the dealer reprogrammed all of the keys you have?

I have seen all types of things cause this from a cell phone tower to water intrusion inside the key causing it to short out.
There must be one thing out of whack in your situation and I think you will have to have some guess and check testing.

Taking the batteries out of all of the remotes at night for a week might be one thing I would try. Another would be moving the cars' night time parking spot.

There is a mode within the factory diagnostic tool that records and displays what sensor triggered the alarm.
Under BCM -> Theft Alarm -> Work Support -> Theft Alarm Trg. This should indicate what the route cause of the failure was.

There is almost nothing in the service manual that discusses this mode and there is no way to view this independently.

[BriLevine]

Thanks so much for the feedback. I was mistaken by saying it ONLY happens at night. There have been a few daytime instances.

As for the remotes, the dealer claims he "checked" all of the remotes and also kept all of my remotes within distance of the car while it was with them at the shop. They also left it outside in the rain, and kept it in their wash bay to try and trigger it.

I did ask the dealer if they could reprogram the remotes or change the frequency of the alarm and they said they couldnt do it....

I am currently waiting for it to happen again. The car has been back in my posession for almost 48 hours, and its been raining too (which is good!).

They claim that they could not determine the source of the fault because each time I bring the car to them, I have previously pulled the fuses to the alarm which clears the computer.

This time I am making a point to NOT pull the fuses if it happens again and get it back to the dealer ASAP.

Do you know what the initial codes are for? They told me it could have been the cause and they cleared them from the system. Obviously didnt help, but they wouldnt tell me what the codes were for.

[SteveTheTech]

Why and what fuse are you pulling.

Hitting the unlock button on the remote is supposed to cancel the alarm.

Haver the dealer check the alarm work support function next time it activates. That will tell them exactly what you are looking for.

[BriLevine]

I was pulling the anti-theft and horn fuses to prevent the alarm from going off again. Yes the unlock buttom cancels the alarm, but somtimes (especially if its in the middle of the night) i would pull the fuse to prevent it from going off 15 minutes or three hours later.

I will definitely check the alarm work support function next time it goes off and i bring it in (no fuse pulling)