2002 Is 300 - Alarm Keeps Going Off

[SachinC]

Hi,

I've had my car for just over a month, however this afternoon the alarm just keeps sounding every 2 mins.

I have to have my keys/remote glued to my hand.

HELP!!!! What can I do to resolve? I have open/shut all doors, boot, bonnet etc...

Thanks,

Sachin

[niloc1200]

Mine suffers this every so often I start it up stop it lock it up then it's fine bloody alarms

[ChrisIS200SportTTE]

Could be interior sensors. Quite a few stories about them going bad including mine. I disconnected mine and no more problems. New ones are quite pricey. There may be insurance implications etc so beware of that.

In the mean time until you know the cause for sure, when you get out of the car, lock all the doors with the button on the drivers door then lock the drivers door with the key not the electric fob. This will lock your car but the alarm won't be armed so it can't go off. Will give you some peace while you track down the cause.

[SachinC]

How do you disconnect the interior sensors please? Where are the sensors? What I did was I turned my interior light panel to 'off' and now it's quiet...not sure how long for.

Cheers

[ChrisIS200SportTTE]

The interior sensors are directly behind the interior light panel. You have to take the roof lining down to get to them.

I don't know how to disconnect them, I got somebody to do it for me.

[SachinC]

What sort of sensors are they? From my Merc days interior sensors are usually ultrasonics with a small grille on the front, exposed. If its behind the light panel and under the roof lining, that sounds a bit odd.

Would be great to know type of sensors and whether the lining needs to be dropped.

Cheers

[ChrisIS200SportTTE]

I don't know what they look like. They are for definate under the roof lining.

I asked Lexus when mine went bad. They confirmed there's an issue with interior sensors going bad as the cars get older. They quoted me just over £200 to fix them. Id read on this forum about them being disconnected so got them to disconnect them for me for a few quid, can't remember now it was a year ago.

These threads helped me.

http://www.lexusownersclub.co.uk/forum/index.php?showtopic=72491&view=&hl=&fromsearch=1

http://www.lexusownersclub.co.uk/forum/index.php?showtopic=63070&view=&hl=&fromsearch=1

[CHUNKY CHIP]

its within the lights structure as a unit simply drop the light out disconnect the wire you see going to the light unit.

Before that do you have a tvss black alarm siren? or do you have a what looks like a horn unit that acts as the sounder as the tvss unit were always palying up a lot try that

[SachinC]

Mines the horn version.

Are you telling me I need to poke a screwdriver into the corner of the large grey unit, drop it out and disconnect the wire? Is that how you do it? When you say pull the wire out, does that effectively kill the light unit completely?

Cheers.

[LexIS200Sport]

Before you resort to disconnecting the alarm sensors, it is worth disconnecting the Battery completely (both terminals) and reconnecting it after an hour.

My car had the exact same issue as yours, and disconnecting and reconnecting the Battery appeared to have resolved the issue for me.