Power loss on start/stop

I have an intermittent issue with my 2008 Prius.

Now and then I push the Power button, the dash flashes like a normal start and then everything goes dark. Then the CD player resets (you hear it moving) and the the car starts as normal. The clock has been reset to 1:00 and radio memory is lost.

Less often, is a loss of power on shutoff. Today I stopped for gas, pushed Power to shutoff the car and it did not go through the normal shutdown. Just abrupt power loss, power windows stopped working, time reset, radio memory was ok. I could immediately go into auxiliary mode and had no problem starting.

I think this has been going on for awhile. I recently replaced the 12v battery after having more 'normal' power problems. Shortly afterwards, the car was dead and the dealer said a low battery in one of the FOBs pulled down the 12v. FOB battery was replaced but I'm left with this issue. I don't think the problems are related but who knows.

I haven't seen any reference to a similar problem. I'm loath to take the car in because it will be fine for days and days so odds are the dealer will not find anything.

The problem is a bit disconcerting because I figure eventually whatever is failing will fail or, almost worse, it is just an intermittent electrical problem that will annoy me for all time.

 

The battery connections were rechecked at the dealer.

I read 11.3v after the car was sitting a couple of hours, 11.8 after use.

 

Nothing aftermarket. When I turned the car on, voltage popped up to 12.0.

Guess I can bring it in and have the dealer check the battery again. What is odd, and I will double check next time this happens, is that the wipers/lights/etc aren't slow/low as they were when the old 12v was on its way out. Plus this is so random. Sometimes happens after car is sitting all night but sometimes after a drive. Today it happened on power off, almost like a system crash vs. graceful shutdown.

I like your QTH and farm.

de kd2mx

 

Thanks everyone....to clarify my voltage readings are low 11.x in Aux, about 12v in On, and ~14 in Ready. I wasn't clear on that.

I have an appt at the dealer tomorrow and will see if they have a clue.

 

Battery tested bad and replaced under warranty.