Is there any way of adjusting the sensitivity of the alarm, mine keeps going off for no reason. It will sit there as nomal and then it will go off twice in five minutes with nothing around the car and then be ok for hours and then do it again.

Any ideas?

Although I've never had a problem with my 3 1993 models if you check out the handbook to find out how to turn off the ultasonic ( movement) sensors you can illiminate such things as air movement due to heat ( quite common in hot weather, ) or airvents left open. Incidently if you can not find this info. try putting tape over the 2 utrasonic sensors. Failing this check for any bonnet switches and adjust then up a bit. Try leaning on the bonnet with the alarn set. You can not adjust the sensitivity but many LS400s have a volume control for the alarm set bleep ( knob under the edge of the dash.) Sorry this is not more helpful.

Cheers lexuslexus, I have tried that whether or not it is working I don't know.

The alarm now only goes off at night so I have come to the conclusion that it is scared of the dark, because during the day it works nomally.

Can anyone advise how to cure it?

Any help would be helpfull.

I always garage mine so I have the option of turning off the ultra-sonic sensors.
If I leave them on, just opening the garage door will cause a disturbance and set off the alarm.

My 2000 model switches these off with a second press of the key.