Crazy "Theft Deterrent System" and/or Door Locks
08-22-01, 01:51 PM
#1
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In an earlier post I indicated that there had been a number of instances in which my 1999 LS400 had been parked in my garage for a period of days, and when I went to use it I discovered that the doors had become locked without my having done it.
Today, the plot thickens. The car had been parked in my garage for about 36 hours. I had not locked the doors; I never do that when the car is in my own locked garage. The ALARM went off! Flashing lights and intermittent blasting horn. I stopped it by UNLOCKING the driver's door. No one had been anywhere near the car during the 36-hour period.
Am I to understand that no one else has encountered this problem?
Since it is a long drive to a Lexus dealer, I want to do everything that I can to get this problem diagnosed before taking it to a dealer, because of course I think that there is a large probability that they will say that they can't find any problem. At least, that has been the case for every other problem that this car has.
Charles Fenwick
Today, the plot thickens. The car had been parked in my garage for about 36 hours. I had not locked the doors; I never do that when the car is in my own locked garage. The ALARM went off! Flashing lights and intermittent blasting horn. I stopped it by UNLOCKING the driver's door. No one had been anywhere near the car during the 36-hour period.
Am I to understand that no one else has encountered this problem?
Since it is a long drive to a Lexus dealer, I want to do everything that I can to get this problem diagnosed before taking it to a dealer, because of course I think that there is a large probability that they will say that they can't find any problem. At least, that has been the case for every other problem that this car has.
Charles Fenwick
08-22-01, 02:43 PM
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My car's alarm has never spontaneously gone off, and I've never experienced the locking phenomena you have, but I always lock the car even when its in the locked garage.
All I can think is maybe theres some faulty alarm sensor in there somewhere.
I will talk to my friend who is a Lexus engineer tonight and see if he knows anything about it. He is part of the design team that built the LS400. He's diagnosed some problems for me a few times that turned out to be really simple adjustments. Might be as simple as reducing the sensitiviy of your alarm. I'll let you know.
All I can think is maybe theres some faulty alarm sensor in there somewhere.
I will talk to my friend who is a Lexus engineer tonight and see if he knows anything about it. He is part of the design team that built the LS400. He's diagnosed some problems for me a few times that turned out to be really simple adjustments. Might be as simple as reducing the sensitiviy of your alarm. I'll let you know.
08-22-01, 03:38 PM
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I'm sorry I can't give you more detailed information but I do remember someone here (clublexus) saying they had the same problem. I don't remember what forum, or when, but someone had the same complaint. I just don't want you to feel more paranoid than you already are. 
Last edited by zushwa; 08-22-01 at 03:41 PM.
08-22-01, 07:10 PM
#4
Charles,
I have a 97 LS400 and have never had the Alarm go off mysteriously like that, but I do have the "Lock-Down" symptoms you are experiencing. I thought it was a feature of the car. Auto-Lock. I have tested it by clicking the unlock on the keyless entry when I have left a store and my car is say 50 yards or so away. I walk casually to it and when I am 10 or 15 feet away I can hear it beep and lock. I would guess it takes a couple of minutes.
Like I said, I think (thought) it was supposed to do that.
Also, as for your alarm, it might be possible if you had your car keys in your pocket, that you could move just right and one of the keys or an object in your pocket might have made contact with the panic button on your remote.
My remote will turn the panic alarm on from a long way off. I remember I was fooling around one day at the dealer and pressed the panic button. My car went off. I was in the show room, the car was on the other side of the dealership, 2 buildings away!
I have a 97 LS400 and have never had the Alarm go off mysteriously like that, but I do have the "Lock-Down" symptoms you are experiencing. I thought it was a feature of the car. Auto-Lock. I have tested it by clicking the unlock on the keyless entry when I have left a store and my car is say 50 yards or so away. I walk casually to it and when I am 10 or 15 feet away I can hear it beep and lock. I would guess it takes a couple of minutes.
Like I said, I think (thought) it was supposed to do that.
Also, as for your alarm, it might be possible if you had your car keys in your pocket, that you could move just right and one of the keys or an object in your pocket might have made contact with the panic button on your remote.
My remote will turn the panic alarm on from a long way off. I remember I was fooling around one day at the dealer and pressed the panic button. My car went off. I was in the show room, the car was on the other side of the dealership, 2 buildings away!
09-17-22, 12:27 PM
#5
came across this post, after experiencing weird glitches and my theft deterrent system randomly going off, annoying my neighbors (and I'm deaf, can't even know when it goes off).. so I pulled the fuse for the theft deterrent. it killed power locks and remote keyless, but that's ok. 1997 ls400. car runs great and all, but have some weird glitches with odometer and tripmeter. odometer suddenly added 300k miles to the actual mileage, my gas gauge went suddenly to half-tank from full-tank in one day. then mysteriously fixed itself, proper mileage, but trip meters don't have a memory due to dome light circuits being disabled because of not being able to detect all doors are actually closed, and no clock. someone suggested my ecu might be starting to fail. if it does, my car is gone. pity, rebuilt trans, newer tires, timing belt service done in last year, new struts.. all within the last 4 years.
09-17-22, 03:48 PM
#6
Why would a failing ECU cause your car to be gone? Rebuilding it isn't the end of the world and for what it is, is pretty affordable. Especially since you've already done quite a few of the major repairs that need to be done as the car gets up there in miles - transmission, shocks, timing belt.
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