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My (one & only) dying key fob

Discussion in 'Gen 2 Prius Main Forum' started by sarahs, Jun 28, 2023.

  1. sarahs

    sarahs New Member

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    I'm hoping someone can answer my basic key fob questions. Backstory is: I have a 2007 Toyota Prius with one key fob only, and I had the fob battery replaced by the dealership about 4 mos ago, and I'd had it replaced about 7 months before that. After this most recent replacement it has started to slowly lose more function, so when I took my car to a local shop for something recently I gave them a heads up that it no longer detects when you're near the door to unlock the car, and that they will need to manually press the unlock button. They went ahead and replaced the battery themselves (I didn't ask them to), and since then I've had to use the physical key to unlock the doors- it works even less than before.

    Given that this fob appears to be rapidly dying, I'm wanting to order a second fob asap after learning you need one working one to program the second.

    My questions are:
    -Can the new fob be programmed even if the old fob is barely functional at this point? It starts the car with physical fob inside, and opens doors with physical key turning, but nothing else.

    -Is there a point at which my current fob will stop starting the car even when it's physically in the ignition- and is that what people are warning about here with then having to replace the immobilizer for 4k?

    -Is ordering a fob from a dealership the only legit option? My local shop (not a dealership) says they can get one for me for $274. Is this a good price? Seems high.

    -Is it worth trying to have the dealership put in a new battery into the fob, or does the fob lose function each time you change it? I feel like it's dancing on the edge of the end so I don't want to do anything that will make it worse.

    Thank you in advance for your help!!!
     
    #1 sarahs, Jun 28, 2023
  2. bisco

    bisco cookie crumbler

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    if you have to put the fob into the dashboard slot, they either put in a dead battery, or upside down.

    call around to local locksmiths for advice and help, but start with the battery. and this would be a good time to get a free load test on the 12 volt battery at an auto supply store.
     
    #2 bisco, Jun 28, 2023
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  3. TMR-JWAP

    TMR-JWAP Senior Member

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    The SKS fob is available on ebay for around $80 and can be programmed using the chicken dance. Unfortunately, your fob may be too far gone to do self programming. You may want to disassemble and clean your original, that m ay help get it fully functional again. Also make certain the KEY button under the steering wheel is in the correct position. It can be either in or out, one deactivates the sks, one allows it to function, but I don't recall which is which right now.
     
    #3 TMR-JWAP, Jun 28, 2023
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  4. dolj

    dolj Senior Member

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    Press the button to the "in" position to deactivate the SKS. Toggle the button to the "out" position to reactivate SKS.

    The correct polarity positioning of the button battery is shown on the inside cover of the fob. The battery itself has + and - marked on it.
     
    #4 dolj, Jun 28, 2023
    Last edited: Jun 29, 2023
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  5. sarahs

    sarahs New Member

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    Thank you all for this info! @TMR-JWAP I will try to clean and disassemble. I read on another thread to use isopropyl alcohol and a qtip- is that what youd recommend? That thread also mentioned getting a 3.2V battery instead of 3V? Anyone have a go-to site for ordering good batteries for these? Thanks again!!
     
    #5 sarahs, Jun 29, 2023
  6. ColoradoBoo

    ColoradoBoo Senior Member

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    The life of your fob battery seems to be awful short. Do you keep the key near the car when you're not driving? The reason I ask is because the car has a system to detect the foband whenever you walk up to the car with the fob, a little red light will blink on the fob because the car "pinged" it. (The same will happen if you walk around a parking lot wit Toyota's...it will get pinged.)
    If the key is stored near a Toyota, the pinging will be pretty constant...using up battery life.
    If it were my key fob, i wouldn't mess around with stronger batteries or rubbing alcohol but just replace them monthly...they aren't expensive and it's easy to do yourself. (Look up video's on YouTube.)
     
    #6 ColoradoBoo, Jun 29, 2023
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  7. sarahs

    sarahs New Member

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    No red light anymore...in fact it hasn't been able to blink that light for a long time. Even when the keyless entry was working in the last year. Does that mean something?
     
    #7 sarahs, Jun 29, 2023
  8. sarahs

    sarahs New Member

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    My thought is to order a new battery and new shell (current one is fraying off, so I worry it will be difficult to do chicken dance while putting it in and out of ignition multiple times), replace the battery, and attempt chicken dance with 80$ fob. I will also check the key/SKS setting under wheel!

    I don't think it's my 12V, could be wrong, but I recently had that checked after it drained and I had to jump the car. That was separate issue- the trunk piece broke off, trunk wouldnt close, so open door light was on for several weeks and drained the battery.The key thing was going on before that happened though. I was going to have car place disable that light but they were able to close the trunk and said the battery was in great shape- I just had it replaced a couple years ago.
     
    #8 sarahs, Jun 29, 2023
  9. bisco

    bisco cookie crumbler

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    a new 3v battery measures 3.3 volts. there's no such thing as a 3.2 or 3.3v battery. all batteries have a higher charge than rating when new and fully charged.

    bite the bullet and pick up a local duracell, etc. from cvs or the like. but make sure the current battery is in properly first.

    and make sure the sks button is in the correct position before doing anything, if you have sks
     
    #9 bisco, Jun 29, 2023
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  10. TMR-JWAP

    TMR-JWAP Senior Member

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    I have even used IA and a soft toothbrush
     
    #10 TMR-JWAP, Jun 29, 2023
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  11. pasadena_commut

    pasadena_commut Senior Member

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    Sometimes battery holders for cell type batteries become corroded where they touch the battery, so that even a new battery acts like it is really weak. Spraying it with electronic contact cleaner might fix that. There is an RFID chip in these things, be sure that it doesn't fall out when working on the fob or it will no longer work to start the car. It could also be that there is a problem with the circuit in the fob, like a cracked solder joint or some component is going/has gone bad. You need to get a 2nd fob in any case, because if this one goes completely it will cost a lot more to make a replacement fob.

    When the battery holder or battery is lightly corroded just pulling the battery out and putting it back in a few times will make it work. Not reliably, but sometimes it works. A thin film of corrosion can be hard to see. Metal scraping on metal can remove it.
     
    #11 pasadena_commut, Jun 29, 2023
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