Factory Alarm

[fipsy]

Afternoon all. hopefully someone can help me here. i own a 1999 is200, since i bought it 2 weeks ago the alarm goes off of its own accord. this happens every couple of nights. i have checked all fuses etc and cant find any problems there. has anybody else had this issue? obviously i could ring lexus birmingham but they will charge. call me tight if you must but always worth a shot at asking fellow lexus owners 1st for free. thanks in advance.

dave

[aido]

Just wondering if maybe your car Battery is on the way out - I've got an aftermarket alarm on mine and that starts to go off when the Battery gets low?

How does the car turn over etc when you start it? Does it come straight up or sound like it's struggling?

[fipsy]

the batteries fine mate. car starts 1st time everytime so dont think thats a problem. thanks for the fast reply

[aido]

No worries mate, welcome to the club by the way :)

Where did you get the car from as think there are some regulations saying if you get a problem within so many days they have to sort it?

You could used to deactivate the interior sensors by pressing the lock again after it's locked initially, on some it deadlocked them and on others it deactivates the sensors, can't remember which is which though - might be worth a go to see if it makes any difference as that would at least rule the sensors out?

[fipsy]

it was a private sale. ive spoken to the guy but the response was...... "IT DIDNT DO THAT WHEN I HAD IT". fat lot of good that is to me ha ha. looking forward to coming to some meets in the future. need to get the car fully sorted 1st though.

[fipsy]

You could used to deactivate the interior sensors by pressing the lock again after it's locked initially, on some it deadlocked them and on others it deactivates the sensors, can't remember which is which though - might be worth a go to see if it makes any difference as that would at least rule the sensors out?

i have tried that. in the owners hand book it states that it turns off the microwave sensors inside. unfortunately it makes no difference

[TigerFish]

Like Aido, the alarm on my GS goes off of its own accord when the voltage drops off too much. Might be worth getting a full Battery check done.

[aido]

That's about as far as my knowledge goes

I think some of the guys were having issues with the cars where either there was a problem with water damage to one of the PCBs in the footwell from where the windscreen had been replaced incorrectly in the past, maybe something like that, or also I think maybe problems with the door closed sensors not working right - might be worth just sitting in the car and seeing if the door open light is working properly as all the doors are opened and closed?

[fipsy]

Ok thanks guys. Ill try what you have suggested. Im on nights again tonight so if it gets quiet ill have a play. cheers, dave

[TommyH]

Think i read somewhere ( maybe dreamt it ) that if you have anything metallicey in your centre/dash tray, if sometimes affects the cencors.

[Rob]

i honestly dont think it makes a difference as all of mine are full of metallic objects and large ones at that and i have never had any probs.

If you have deactivated the interior sensors and the alrm still goes off then its a door switch that is faulty. To fully check if u have deactivated the sensors ( as yours is a 1999 model) have a window down, get out of car, press key fob nad u get 2 indicator flashes, press it again and u will get 5 flashes. wait about 1 minute then stick your arm thru the window and wave it about - alarm should not go off. Try the procedure again but only with a single key press as the sensors should then be armed.

also try closing the air vents - is odd but sometimes works

[deckie77]

Welcome fipsy,

I have a 2002 is200, i had the same problem when i first got it, it would go off in the middle of the night and all sorts, following the disable in the handbook stopped it from happening, but this cycle is re-set once you open/start/your car again, so you will have to re-do this procedure each time you lock it.

Lexus aberdeen told me to remove all metaics in the centre console like tommy said, but i had none in there in the first place, so i dropped in past lexus one day when i was in Aberdeen, and it and one of the mech's said he had seen this a few times, and replacing the interior sensor (s), i think the one in the centre light was the fix, i was told it would cost me near £200, or he could disable it there and then and send me on my way, i chose the latter.

I live in a quite quiet place, keep the car round the back of the house, so i felt ok having that part of the alarm disabled.

Of course you may feel you require this

[ColinBarber]

on the GS there is a sensitivity adjustment on the microwave unit behind the centre console near the gear selector. Not sure if the IS uses the same alarm system.

[fipsy]

afternoon all. right ive tried testing the system ie:- opening door/boot with key when system is set, works fine. leaving window(s) open after system set and waiving hand inside, works ok. and also locking then locking again with window(s) open and waiving hand around sensor, works ok as it doesnt go off then. ive checked the Battery and after the car has been sat all day/night its reading 12.40V which is normal and with engine running its reading over 14V which too is normal so i am completely lost as to what the problem is. oh ive also removed all objects from the center pockets. not sure which one was mentioned in the above posts but removed from all just to make sure. anybody have anymore clues as to what it could be before i make the dreaded call to lexus?

[ColinBarber]

so now you have confirmed you can turn off the interior motion sensor have you done so? Is the alarm still going off?

[redz_UK]

as mentioned above,

check the door switches and close air vents..

[janet]

Following this with great interest as I have exactly the same problem, and posted about it months ago...the problem went away, but, has just returned...once in the early hours last week, and last evening about 7pm.....I too feel the dealership coming on, so far the sensor disconnection post sounds like a plan !

[janet]

Well, no-one who had actually replaced an alarm responded to my post asking the question.

I went to the dealer, and after lots of discussion it was agreed that I would be better to fit an aftermarket alarm...off I trots to the specialist...they looked at the system, confirmed that the alarm and immobiliser are seperate, but that they could not install an aftermarket, as the alarm is hooked into the ECU.

Back to the dealer then, they were sceptical that the internal sensors could be disconnected without cocking up the system, but they tried it and it has worked...

Two more things,

Now I wait to see if it has cured the problem....(if not it's MONEY)

and,

I rang my insurance company first and established with them that i would still be covered if the sensors were not working...I will now confirm that to them in writing (I'm that sort of person...make sure my ar## is covered).

There you go then, hope i don't have to post again!

[ColinBarber]

on the GS there is a sensitivity adjustment on the microwave unit behind the centre console near the gear selector. Not sure if the IS uses the same alarm system.

There isn't an adjustment on the IS system so if the interior sensors are playing up the unit needs to be replaced. Located in the interior light unit.