Ls400 Alarm Going Off

[Baldeagle]

Hi Everyone,

Parked my '98 LS400 in a busy Industrial Park today, walked away after locking with the remote fob, I'm 100 metres away inside the foyer of this garage, and my alarm goes off, go out, stop it with fob, return to office, 2 minutes later, same thing, happened 6 times, to my acute annoyance and embarrassment,it was then driven in to the garage work-space to have an MOT done,no problem then, or since, ( fingers crossed) -I might add there are two wind turbines in this car-park area, I was parked under the one that wasn't turning, though the other one, 15 metres away was, could this have set off my alarms? or, as it was raining heavy at the time, could damp have got into the alarm-sensor? any help, or suggestions would be greatly appreciated, thanks.Iain.

[black400]

My 99Ls400 did this a few times , cctv cameras can cause this, and wifi signals. it was a big problem with Range Rover p38s.It even does it out side the house if i park to near the wifi. Hope this helps

[abs66]

My alarm played up a lot when my old Battery was failing even though the car was behaving itself. New Battery seems to have done the trick.

I'm not saying it is the Battery, but worth checking how old yours is if you haven't already.

[gkkes]

My alarm going off heralded water in a loom plug at the bottom of the windscreen.

There's a transmitter on a building at North Cheam which completely flummoxes Scorpion alarms.

After much head scratching and phone calls, I had to push the car 300yds..... Started fine!

There's a great restaurant there and stupidly did exactly the same thing a few months later!

[Keith Bowler]

Petrol stations is a bad one for me, well at least my local Esso garage is.

[The-Acre]

My alarm going off heralded water in a loom plug at the bottom of the windscreen.

There's a transmitter on a building at North Cheam which completely flummoxes Scorpion alarms.

After much head scratching and phone calls, I had to push the car 300yds..... Started fine!

There's a great restaurant there and stupidly did exactly the same thing a few months later!

When I had my 93 LS the alarm went off at 4am (no Christmas cards from the neighbours that year) When I opened the door the inside was soaked, turned out to be the sun roof drain holes being blocked, so it could well be a damp problem. As soon as the car dried out the problem stopped.

[Baldeagle]

Mmmm.... It can't be the Battery, as I bought and fitted a new one two weeks ago, -the car is used regularly, so it's being charged efficiently, sounds like I'm not the only Lexus owner who experiences this problem with the alarm, -don't suppose there is an alarm-immobiliser -switch anywhere on the LS?

While on the subject -since owning the Lexus, every time I pass through the security bars of the doors of any Tesco, Morrisons, Halfords, Currys, -any major store-outlet in fact, I set-off their security-alarm,-only happens when I've the Lexus remote on me though........

[ambermarine]

Try changing the Battery in your key fob

[Baldeagle]

Brand new batteries in both my key-fobs.

[ManicMark]

Have you got any metal objects in the centre arm rest as this increases the sensitivity of the alarm & lots of things can set it off Happened to me on my first trip to Germany 2 lpg adapters in the centre arm rest. Sliding door sensors on a shop 30 meters away kept on setting it off & diesel vans going past.

[mick4545]

during the cold snap, (-7), the alarm on my 600 went off. This is the first time its done it, and if it wasn't the low temp that did it the only other thing I can think of is the cover on the front cup holder was open. I don't think I left it in that state and Ithought maybe something had contracted in the catch, causing it to fly open and set the alarm off.

[Cotswold Pete]

I had same problem with my 2000 LS400.

Happened near a Sainsbury superstore and in lane at back of house.

Both times seemed to me sorted by opening sun roof and then closing. Only tried this as having spent 10 minutes annoying people shopping at Sainsbury, I sat in car and it said that moonroof not closed, when given the naff weather it has not been opened for months.

As I do not experience high levels of in-car moisture, I assume sunroof drains are fine.

I'll keep an eye on the Battery, as not sure how old it is, as only had this car for 9 months.

[Baldeagle]

A lot of replies to my thread mention battery-condition, I replaced mine with a new one very recently, I get a lot of opinions outside this group from mechanics, owners of high-spec cars like Lexus,they talk about moisture and dampness affecting the alarm-sensors, nice to know about that, but it don't cut much ice, when the alarm goes off repeatedly during the night, and the neighbours start complaining! I have heard that some Lexus models have an alarm disabler switch under the dash, but I don't think my one has-mores the pity, -wonder how big a job it is to disconnect the damn thing, yes, I know, insurance problems, but it would be nice to have an worry-free alarm!

[Parrot of Doom]

Remove metal components from the centre armrest, that should sort it. If it doesn't, I recommend getting an auto electrician to diagnose and repair.

[CHUNKY CHIP]

disconnect the siren no noise then but still alrm works

it will reset then after false alarms if it does go off at anytime immob still works just no noise....if neighbours are a worry if it does have an issue

Also siren plug wetness and corrosion this area was also a popular fix on the tvss and scorpion systems under warranty also many had a shall we call it a special sleev fitted to stop water entering plug also as a mod ( did it work well no) just a simple repostion is what was done

Most popular time found for false alarms is usually just as day breaks depending on time of year but 4-5.00am is a good one

temp change inside plastic expansion ocurs within the trim and false alrms if interior sensor is high set

also with glass roof vehicles this is more so in sunshine

false alrams in wind also along with electrical intereference from outside eg turbine wifi all them have a bad effect on the alarms internal sensors microwave or other

spent many an hour adjusting sensors and shock sensors etc

funny not for the neighbours well depends how far they are away from the car at the time

[steve20vt]

Old post I know,  but I'm having similar issues on my 97 ls400. Had a spate of going off at 4 am but it's been fine for weeks and now it's at it again,  except pretty much any time of the day. 

Goes off, reset it then ten mins later it's going off again. 

The Battery is good,  there's nothing in the armrest. Only thing could be it's been raining quite heavily and then bright hot sunny days. 

Had to leave it unlocked last night to save the neighbours moaning. 

Is there a switch to disable it does anyone know? 

[Malc]

...........  there's no disabling switch to my knowledge ...  what i did once was to remove a specific fuse from under the bonnet gubbins .........  that disabled the alarm but also the steering adjustment and something else i think too  .............  it was troublesome so I put the fuse back and mostly, ( just mostly ) the alarm doesn't misbehave.

When it does it's a right royal pain in the a.se  ....  even leaving a window slightly ajar and locking the car doesn't stop the alarm doing it's stuff over time.

Of course it might just be someone trying to break into your car !

I know of no solution in the 5 years with this otherwise wonderful young lady  ( 21 years this year ......  it's a very small price to pay for otherwise brilliant motoring )

Ah, I remember, once in a back street in Spain, I parked up to visit the local sites ( a disused bullring ), the turning was built up both sides and as soon as I walked around the corner I could hear the alarm going off ........  I returned and left the car unlocked ........  I think someone on here told me it might have been someone's wifi affecting the sensitivities of the dear old lady.

Malc

[runsgrateasanut]

My alarm went off yesterday when I opened the boot with the spare key.  Has done this before on occasions. Don't need to unlock the car before opening the boot surely? Is it another known gremlin?

[steve20vt]

Mine does that too, but if you use the remote to open the boot it's fine. 

Nobody was trying to get in it, was the afternoon and I could see it on the drive while trying to watch the grand national (won £23 yay)

It turns out I do have metal in the armrest,  5 wheel nuts, a set of keys and an egr blanking plate I've not got round to fitting yet.

It's been fine today so far.....

[The-Acre]

It is surprising that no facility was ever given for disabling the alarm.  Keep us posted on whether removing the metal from the car makes a difference, after all, that is quite a collection you found there!

[Titch LS]

On two occasions recently I've left my mobile in the central console. Both times it set off the alarm. Not straight away mind, but it did go off. It's not done it since I removed the offending item. I'm sure it's not coincidence. Iv'e learned the lesson.

[oldhazey]

No lexus/scorpian alarm fitted anymore,all ripped out and replaced with a Hawk system,although i have lost boot release from inside the car 

 

[Bowlerrob]

Hi, help needed please have just purchased a 95 ls400 with imobiliser problem think it's the unit but is there a way to bypass altogether do you know?.

[The-Acre]

7 hours ago, Bowlerrob said:

Hi, help needed please have just purchased a 95 ls400 with imobiliser problem think it's the unit but is there a way to bypass altogether do you know?.

Rob, if its not an alarm problem you have I would suggest making a new post describing your problem.  This is an old thread now so if won't be read by too many.  As far as I know you can't bypass the immobiliser but it would help you if you give more detail.

[steve20vt]

There are individuals on Facebook groups that cater for people who put the 1uz engine into other vehicles who can disable the immobiliser in the ecu. 

It does mean sending it away but it doesn't cost much as far as I'm aware. 

You'll need to join groups like "1uz swap parts uk" and such like.