2005 Prius Won't Unlock / Fob Doesn't Work

12 volt battery sounds like it is shot if it is original. I just went through this on my 05..

There is a jumper lug under the hood in the electrical box, driver side near window. Take the cover off the box and you will see a red cap over the jumper point. Jump it to a good car battery for 5 minutes and try to start the car.

If you are a "CSE" this should be within your skill level. If you are in sales find a " CSE" to help you.

Jerry, recently retired FMTS

Edit: just re-read your description and realized you can't get into the car. The mechanical key being able to unlock the door should not be affected by electrical failure. That is strange. Regardless if your 12 v battery is original it is time for a new one once you get into the car.

 

The flashing key light on the dash is completely normal and in fact has been there forever. It would be very weird if you can't get into the car using the mechanical key, but if you can't then your only choice is to call a Toyota dealer's open-and-jump service to jimmy open the door. Then with your trusty voltmeter *before* the guy jump-starts the car, measure the 12V battery voltage. If you are lucky it will be dead (that is, less than about 10V) and the solution will be easy: get jumped and drive to the dealer for a new battery. If the battery reads 12.0 to 12.8 V then there is some deeper problem mostly likely requiring a tow and dealer diagnostics.

 

The problem here is that the mechanical key works two ways: 1) It activates the power locks, 2) It will mechanically unlock the driver's door.

When you use the mechanical key with functioning power locks, a small turn of the key closes an electrical switch, causing the power locks to activate.

If, however, power is not available, such as having a dead battery, you have to turn the key harder, and pull the door open while holding the key turned. It's not intuitive, but it does work.

Tom

 

Fifteen (15) years later and this happened to me, 2005 Prius. Thanks for your post I got it to unlock...

 

Aww crap, now I gotta try it! And if that works, I'll disconnect the battery and roll down the window ... just in case and try it again.

 

I had to open my with bad battery before. It almost feels that if the battery is actually close to give up, is worse than if dead.
Almost like the car knows you have the fob, but there is not enough power to use it.
I have been able to solve the problem, by simply walking away from the car for a bit of time, and coming back and quickly trying to open with the key.

 

i never knew this