Single Beep When Turning Off a Prius

27/02/2013 – Please note the original article refers to a CR2032 battery which is only compatible with the fob for the second generation Prius. The third generation Prius uses a smaller CR1632 battery!

In the last day or two I have found the Prius emitting a single beep when I have parked and turned off the car. Normally, the car will shut off without a sound when I push the ignition button so obviously this was a bit strange.

Anyway, tucked away in the manual I found out that a single beep when turning off a Prius means that the battery in the fob is running low. This made sense as for a while, on and off, the car wouldn’t recognise that I had the key inside the car if I left it on then exited and re-entered the vehicle. Furthermore, I have had the car for just over three years now so it makes sense that the battery would be reaching the limit of its stored capacity.

Anyway, I will be going out to find a replacement CR2032 battery tomorrow and then swap the battery out. Needless to say, you don’t want to let the battery run completely flat as you will face problems getting into the car (although you can use the hidden physical key inside the fob). You won’t be able to start the car by keeping the key in your pocket though so you’ll need to plug it into the fob receptacle to get the car to start.

You can find a replacement battery at shops specialising in automotive products, batteries, general electronics or car fob programming.


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    • Ann-Marie on February 20, 2013 at 05:32
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    Thank-you! I have been thru the manual and could not find out what was the cause of this beep—it only seemed to happen only after driving the car a distance vs just to the store.

    1. My pleasure – the Prius manual was quite big for the 2008 model I owned and even bigger for the 2012 I now own so trying to find anything in there is like scouring an encyclopedia!

    • Steve Schade on February 27, 2013 at 10:55
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    Thanks Boyd. That makes perfect sense to me. I was wondering about the single beep as well. In fact, some times I had to get my pocket almost up against the door before the smart key would unlock when I touched the door handle. Is it best to by the batterie at a Toyota dealer or do you know a better source?

    Many Thanks,

    1. You should be able to buy replacement batteries from automotive shops or places that specialise in electronics or batteries. The CR2032 is a fairly standard coin type battery so you shouldn’t have to look too far (if the fob is for a second generation Prius, the third generation Prius fob takes a smaller CR1632 battery – I’ll update the article to reflect that later today).

      I have to say that you need a bit of skill and patience to dismantle the second generation Prius fob – it is a little fiddly compared to the third generation fob!

    • Steve Schade on February 27, 2013 at 13:44
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    Mission accomplished Boyd. You are right about skill due to the micro screws that hold the battery cover on. I recommend a magnetic micro phillips screw driver. As a result of your article, I discovered that the key fob on my old Buick that my youngest daughter drives also had a weak battery and uses the same battery as the II Generation Buick. Problem solved by going to Walgreens this evening.

    Thanks again for your advice.


    1. No sweat at all! 🙂

  1. I just changed my Fob Batteries CR 2032 and I still got the single Beep when the car is turned off .. Do I have to reset anything to clear this .. Thank you

    1. Shouldn’t need to but you can try putting the fob in the fob receptacle in the car next time you drive which may help the car realise that there is a fresh battery in the fob and clear the warning. After that see if that eliminates the single beep.

  2. Well Boyd, I just got back from the store ,and I’m sad to say it still beeps ,,Could it be the fact that it sat at the airport for a week or 8 days and the 12 volt battery is going bad … It’s a 2009 I bought used Lease return ,and have no idea how old the Battery is ,,or could it be the fact that I threw a 50 pound suit case in the back seat ,,maybe there is a censer in there ,, I get no warning light on the dash ,,everything works good …. How long can I live with that beeping going on ?? Thank you for all your input ,,,,If I take it to Toyota ,,, you know how that will go down …. Thanks again ,, AL

    1. Well, my second generation Prius from 2008 still had its original 12V battery in it when I sold it to a relative and is still running on that battery. However, I don’t think the beep would be caused by a weak 12V battery or putting a heavy suitcase on the back seat (no sensors there as far as I know).

      If you have two fobs have you replaced the battery in both?

  1. […] to be confused with a single beep when turning off a Prius, you might also encounter a single beep when opening the driver’s door on a third generation […]

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