SmartKey headaches

This is unlikely your situation, but when I had to replace my 12-volt battery, I found that the hatch seal had leaked rainwater into the compartment (above my right wheel) containing the battery. The battery was setting in two inches off water. I drilled a couple holes at the very bottom (with a short enough bit that I didn't kill a tire). Just a wild thought. You've probably been in the battery compartment and found no water, anyway.

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My 2005 SKS may be different than your 2009. Anyway, SKS means a bigger 12 volt battery than non-SKS, which is a good thing.

I turned off SKS using a push button switch that is under the steering wheel. Look in your 2009 owner's manual for instructions. On the 2005, it's not easy telling on from off. By turning off SKS, my 12volt battery should last longer.

My SKS is turned off. Having to insert the fob to enable starting the car is not an issue.
Having to push a button on the fob for locking and unlocking the car door(s) isn't an issue for me.

You do know about the metal key in the fob, right ? It's a failsafe way to unlock the door.
And, the fob has an rfid chip that is the "key" for enabling starting the car. The rfid chip doesn't use the fob's battery. The car "reads" the rfid chip when the fob is inserted in the slot. The rfid chip may also be "readable" by just putting the fob on top of the "Start" button.

Hope that helps. Good luck

 

One of my Smartkeys became dumb some years ago, chip died or something, but if I stick it in the start hole, car runs.

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Have you tried replacing the battery in the key fob?

 

Yes. No luck. Toyota service even did it for free. Pronounced it dead. Had been shorting (i assume) causing car alarm to go off, once in middle of night (cops knocked on door), not long before it quit altogether.

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welcome o/p! you need to educate yourself a little more before making rash choices.

1) the prius 12v does not need a lot of fussing, just a little.

2) i don't know how long you back pack for, but a healthy battery is good for 6-8 weeks.

3) start with a battery test. if you don't want to do it yourself, take it to an auto parts store, they will do it for free. if you want to test it yourself, there are plenty of threads here, or just ask.

4) if the battery is original, replace it now.

5) once you know you have a healthy 12v, and two healthy fob batteries, no more fussing necessary.

6) if you want to turn off sks while away for weeks at a time, that isn't a bad idea.

7) all the best!

 

No, absolutely and positively WRONG.
The only people who have constant 12V battery problems are those who have minimum use. Like they only drive 2 days a week and those trips are less than 10 miles each.

YOUR problem most likely is that your battery is now 7 years old. That's a bit past the average life.

Get a new name brand battery. Charge it fully before installing. Check the charging voltage.
Likely you will get another 5 years before you have to worry about it again......unless you are one of those "minimum" drivers.

 

Dealer wanted $100 labor to replace battery. Heck no, I said. Then I did it. It's not your dad's Buick battery. Lots of dis- and re-assembly. No question I'm paying $100 next time since I'm now 70. I vaguely recall it taking almost three hours. Then again, I was 65 or so. And had to find a drill and a bit and drill a couple holes to let out water that hatch seal had let in....

Posted via the PriusChat mobile app.

 

re: " One of my Smartkeys became dumb some years ago, chip died or something, but if I stick it in the start hole, car runs. "

Junk gets into the fob and builds up on the circuit board. Dust and pocket lint were shorting some wires and leads on one fob. I cleaned it using toothpicks and can of compressed air, the stuff used to clean computer keyboards. Now the fob works fine.YouTube has some videos on this.

 

but if you insist, there's no reason you can't leave sks off. they say temporary, because they assume you want sks.

 

I assume you have to pry apart the two halves of the fob case (without breaking it!) and not just reveal the battery compartment, but I also assume it would help to remove the battery before prying apart the case. I also ALSO assume I'll need to remove the circuit board so as to get at any contacts on the dark side, unless there just aren't any exposed metal thingies back there. Finally, I suppose I should also make an appointment with a hand surgeon and do the repair that morning.

Gen 2 (2006) and Gen 4 (2017)

 

If this is the first time the fob case is being "pried apart", then go slow and give the old glue time to loosen. The fob case and the circuit board are like most Toyota's, built to last. They just don't self-clean.

If you remove the circuit board, then you might as well discard the old fob case and buy a new one on eBay. . . . if a new fob case is used, be sure to also move the rfid chip to the new case. DO NOT leave the rfid chip in the old case, else the new fob will be totally worthless since it won't be able to start the Prius.

So, no, didn't remove the circuit board. Just followed the YouTube video. . . .

One is titled "Remote Control key (FOB) TEAR DOWN 2nd gen PRIUS 2004-2009 disassembly" kruto