hi mark my ls400 is a brilliant car .i also have a 2001 ls430 .i love them both.i left the 400 under a cover whilst the weather was bad. the alarm kept going off at night .after rwo sleepless nights i took the car to lexus stockport .they could not find a fault. i have put a good quality triclkle charger onto a new battery and am going to hope for a good nights sleep.thanking you for your interest dave