My 2008 LR3 works great. Then, sudden;y and unexpectedly, the locks engage and the lights, radio and a/c all stop working. The flashers come on and will not turn off. The words, "System Check in Priogress" appear. The car will run, but will not re-start if I shut it off. Eventually, the functions return to normal. Then, it happens again./ The dealer had it for three weeks and couldn't find the issue. It is not the battery. Do any of you have ideas?

Thanks -- I'm stumped.