Prius locking constantly.

[Ogg]

Hi there, I’m new here but I have been searching for a solution to a problem with my wife’s 2008 Prius and have had no luck, so I am hoping one of you can offer some advice. 
Three days ago the car just started auto locking itself, now I know they do this after a certain amount of time for security, but this is when it’s already locked? The solenoids are clunking, indicators flashing it’s just as if someone it constantly hitting the fob button. It has now drained the Battery so I am recharging that as I type. 
The fob seems to be working fine, the red light only lights when the button is actually depressed, and the fob is stored a fair distance from the car inside the house so I don’t believe it’s sending a lock signal. 
any ideas from anyone on here would be most helpful. 
When it first started, I went into the in car diagnostic screen and the Battery voltage was fine so I’m pretty sure it’s not a bad Battery. 

[kithmo]

Do you have a spare fob ?

 

[Ogg]

No unfortunately not, we did get a spare with the car but my wife lost it months ago. I have made sure it is not in the car. 👍🏻

[Gerg]

Hi,

As it's so easy to do, it might be worth disconnecting the 12v Battery for 10 minutes, just so all the ECUs are reset.

You could take the button cell Battery out of the remote key, just to be sure that it is not malfunctioning.

On some later Toyotas it is possible to turn off the radio remote function through the car's on on board dash menu, perhaps this function is available on your car? If it is disabled then perhaps this changes the symptoms?

[Ogg]

Thanks for the reply Gerg, the Battery is off at the moment so I will see if anything has changed in the morning when I re- connect it. 

[Joseph D]

Before reconnecting the 12 V Battery, take the CR2032 button cell Battery out of the remote.  Use the little metal key in the remote to lock/unlock the car and put the fob in the slot to start it.

Do this for a few days and see whether the auto locking behaviour changes.

If the auto-locking behaviour stops, reinsert the fob Battery (it would be good to measure the voltage while it's out of the fob), if it is 3 V or better.  If it is not at least 3 V, replace it with a fresh battery that is 3.3 V.  Let us know if the behaviour returns once the battery is re-installed.

Let us know how you get on.

[kithmo]

19 hours ago, Ogg said:

No unfortunately not, we did get a spare with the car but my wife lost it months ago. I have made sure it is not in the car. 👍🏻

Could it be lost in the house, down the back of the sofa, in a handbag etc. or somewhere where the buttons are getting pressed ?

There was an instance of a Gen 4 locking/unlocking on it's own, turned out to be one faulty door lock.

 

[Ogg]

Hi all, this morning I removed the Battery from the fob, then reconnected the Battery in the car. ( the alarm then went off, oops 😳)

started the car fine with the Battery less key. No random locking going on, I have now replaced the fob battery. All seems well for now. 
Thank you all for your help and advice. 😊