Key FOB no longer locks/unlocks after driving.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by PRIINZ, Feb 7, 2018.

  1. PRIINZ

    PRIINZ New Member

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    Hi All,

    Got a bit of a weird one here that I can't seem to figure out.

    Few days ago I accidentally inserted a friends keyfob and tried to start my car. Needless to say it didn't work however I quickly grabbed mine and all was well. After this however I noticed that my fob wouldn't lock or unlock the doors. It still starts the car just fine.

    After a bit of troubleshooting I have discovered if I let the car sit for some time the fob works fine. If I then insert the fob and start the car it no longer works correctly. I don't even have to put it into drive, just the act of starting the prius causes the car to no longer respond to my fob (If I sit there and mash lock a bunch of times it sometimes responds but then won't unlock and vice versa).

    Anyone have any ideas how to resolve this issue? It's rather annoying having to use the manual lock to lock my car every time I use it.

    Thanks
     
  2. dolj

    dolj Senior Member

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    Hi PriiNZ and welcome to PriusChat.

    I don't think putting the wrong key fob in should upset the car.

    How old is the battery in the key fob? When the fob fails to lock/unlock, does the red light on the fob illuminate when you press it?

    When you say the manual lock, do you mean the physical key from the fob?
     
  3. PRIINZ

    PRIINZ New Member

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    Thanks for the welcome Dolj.

    The battery is a few years old however it's not a battery issue. Both fobs have the same issue and if I leave the car for 5 minutes everything responds perfectly fine without issue. However yes, the red light illuminates on both fobs and I do mean using the physical key.
     
  4. dolj

    dolj Senior Member

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    I can't say I have heard of this issue before, is the Prius a NZ new or an import? Does it have SKS – ie remote entry and start?

    Have you checked the voltage of the 12 V battery recently?
     
  5. PRIINZ

    PRIINZ New Member

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    It's actually a Japanese Import. Everything is in japanese and mine isn't up to scratch haha. No SKS as far as I am aware but I'm not sure what that is exactly
     
  6. dolj

    dolj Senior Member

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    Good to know, as I believe the Jap imports key fob use a different frequency range. Not sure if that is relevant, at the moment, but it is if you need to get a new one. They are different part numbers.

    Have you checked the voltage of the 12 V battery recently?
     
  7. PRIINZ

    PRIINZ New Member

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    No I haven't been able to figure out how to get into diagnostic mode
     
  8. dolj

    dolj Senior Member

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    It's better to just use a voltmeter on the battery terminals or the jump start point.
     
  9. PRIINZ

    PRIINZ New Member

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    Ok cool, I'll look into it when I finish work and let you know.

    Thanks
     
  10. PRIINZ

    PRIINZ New Member

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    Sooo...12V battery is good. =S
     
  11. PRIINZ

    PRIINZ New Member

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    *Bump* Any other ideas?
     
  12. dolj

    dolj Senior Member

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    Sorry I missed seeing this. SKS is Smart Key System and essentially is the ability to remotely lock/unlock the car without getting the fob out and pressing buttons and the ability to start the car without inserting the fob in the slot. It is also called keyless entry and start. The easiest way to know if your car has SKS is the fob has a silver logo on the back, there is a button on the dash under the steering column labelled "Key" and the front door handles have a black button on them, as does the rear hatch.
    So when you say it was good, what were the open voltage; loaded voltage and voltage after resting overnight?
    Only other idea, is may be one of the buttons is sticking on and preventing the lock/unlock from working. Although I don't see how this can be related to putting the fob in the slot.

    Do you have a second fob to try and see if that behaves normally or the same as the original?
     
  13. PRIINZ

    PRIINZ New Member

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    So no SKS I need to use the fob to lock/unlock and I have to insert it into the dashslot to start it.

    I had a friend take a look at the battery as I have no idea what I'm doing. He said everything looked about as expected.

    I do have a second fob and it behaves exactly as the other one does.
     
  14. dolj

    dolj Senior Member

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    This is sort of good news in that it is unlikely the problem is the fobs. The sort of bad news is that it is possibly something wrong vehicle side.

    Unfortunately, I haven't come across anything like this before, and I assume the same for other PriusChatters, as no one else has chipped in.

    Maybe it is time to have Toyota look at it and see what they say.
     
  15. Locksmith

    Locksmith Member

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    Rule number one when diagnosing or servicing any battery operated electronic device is change the batteries. It’s cheap, and you get to start from a known standard.

    I have had customers replace the batteries in their safe lock when it starts acting up. First thing I do is put in MY brand new batteries and that almost always solves the problem.
     
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