2006 Toyota Prius Starting Problems

My brother in law and sister are away for vacation and they left me in chaege of driving their cars (once/week). Both of them are identical Toyota Priuses.



I follow the proper procedure to start them, but one of them seems to be draining its battery (in between the times I go to drive them).



There doesn’t appear to be anything turned on (lights, radio, underhood or trunk lights, etc) that I’m aware of that would cause this to happen.



I did find out that when my sister took this car (it’s her car that has the problem) to the car wash, it wouldn’t start up when she was done.



It went to the dealer and they could find nothing wrong with it.



Anybody out there have any idea what could’ve happened to cause this?



Thank you.



Mark B handler

I forgot to mention that the car can be started by jumo startting it.