Beep???

[daniel]

Recently my 2004 Prius has begun doing something it never did before: Maybe half (?) the time, when I shut the car off, it makes one long beep. The other times, it does not.

No other symptoms, no apparent problems. It shuts down properly, and starts up again when I want to start it.

I'm shutting down as I always have: Press the Power button while stepping on the brake. (I do not put it in Park first, and never have.) I keep my foot on the brake until the dash lights turn off.

Any ideas as to what it might be beeping about?

[Rokeby]

daniel,

At four years old, your 12V batery is at an age that often results in reports
of symptoms of electronic weirdness.

You're in a coldish climate which also stresses the 12V battery. Have you had
it tested? It might be time for a replacement... non-OEM of course.

[hschuck]

I believe that a single beep at turnoff is a warning that the battery in the fob is getting weak (applies to SKS equipped vehicles only). I had that beep intermittently some time ago but it hasn't happened lately. I'm waiting to get a better correlation before I change my fob battery. My battery is almost 4 years old and yours is in that range also if it hasn't previously been changed.

[TonyPSchaefer]

A-Ha!
It's not just me. Priapus has begun beeping at me as well. Like yours, not all the time and I have yet to have a problem with him starting. But all the same I'm planning on replacing the 12v in the summer unless it all-out dies before then.

[firepa63]

It's the battery in the SKS fob that's causing the beep. The same thing happened to me when I had my 04 and had never replaced the fob battery. Replaced the battery ... no more beep at shutdown.

[daniel]

Wow! Once again, PriusChat rules!

My 12-v battery was replaced a year or so ago (I don't remember the reason, but it seemed reasonable at the time, given its age.)

But my fob battery has never been replaced. It's not immediately apparent to me how to replace it. Can it only be done by the dealer? Or does it come apart if I pry at the little hole with a screwdriver?

[efusco]

Daniel,
Remove the mechanical key,
Slide off the back...it can get sticky over time, but it will slide.
There are 4 small screws that you remove with a jeweler's screw driver to expose the battery. It's easy from there.
2004 Prius Keyfob Battery Change

[daniel]

Hmmm. I can see where it's supposed to slide. The back moves easily the tiniest bit, just enough to slide the narrowest eyeglasses screwdriver blade in, but then it stops as though it's catching on something. I can even lift up the back, but I cannot slide it free. I tried on the spare also, the one that's always been in a drawer, never exposed to dirt, and it behaves the same. Is there some other trick to getting it open? It really does not seem to be sticky with grime. It seems to be catching on something after it slides the width of a fine pen line.

[richard schumacher]

As a test, if your spare fob has been mostly unused try it first and see whether there is a beep.

Note that the cover slides off parallel to the long axis of the fob. That will help you locate places to pry with a small screwdriver or pick if you can't slide the cover off with your fingers alone. I moved my spare fob's old battery to my primary fob and put the new battery in the spare. No sense letting the old one die unused...

[daniel]

I can see how it's supposed to slide, because it slides that teeny tiny fraction. But even getting the screwdriver into the space and prying does not move it further.

I considered switching fobs. (No point in switching batteries, when I can just put the one I've been using in storage and use the one I've been storing.) But I figure the battery probably loses more from age than from use. They're probably both near depleted. So I'll replace one battery, since the spare fob is only if I lose the primary one, and the spare does not need a battery since it can always go into the slot.

But first I have to get it open. And neither one of them wants to open. Both seem to be jamming against something after sliding the thickness of a business card.