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2005 Gen 2 Key Fob/Smart key Troubleshooting - Not the Fob

Discussion in 'Gen 2 Prius Technical Discussion' started by Jules C, Apr 5, 2022.

  1. Jules C

    Jules C Junior Member

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    I’m 95% sure the issue with my 2005 Prius key fob smart key not working is NOT the key fobs. I’ll go get it tested for sure. But I replaced both batteries and used both key fobs and no I didn’t have both fobs near each other or in the car at the same time. I have both original silver key fobs, neither work.

    I also know the button is out and what that is.

    Here’s what happened:
    Over a period of months the key fob smart key would work closer and closer to the car. Until finally it stopped and I can only open the car door with the hard key and start the car with the fob in the slot. My hunch has been an internal electrical issue or dead antenna. That doesn’t mean that’s correct.

    Questions:
    1)How would I know about a top level locksmith? Is there a term I need to search? My local locksmith didn’t know how to diagnose anything.
    2)I’ve never been give a code related to smart key key fob, what can I diagnose/check to find out what is the problem?
    3)I’ve seen the video on reprogramming the a new key fob. I’m not sure the fob is the issue, but if it were, I thought it’s hard or impossible to get a new fob because the fob should have had a vehicle ID associated with it. Is there anyway to buy a working key to replace? I’m still skeptical this is my issue.

    If there’s anything I didn’t add or clarify please let me know.

    TLDR
    I can not hand unlock the car, start it without being in the slot, and no buttons work. I’m pretty sure it’s not the fobs and it’s something internal. I have both original key fobs and put brand new batteries in them twice.
    thanks so much
    J
     
  2. Tombukt2

    Tombukt2 Senior Member

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    I'm sure you're on to something here as i have a prius that's almost the same my buttons do work my display does not light up consistently and i'm almost positive but that's something to do with the remote and the slot amplifier if i play with the system just by taking the remote out putting it back in turning the smart key off at the button below the steering wheel and cycling the power button in the systematic silly way that i do every morning the car will light up and run all day all during the day when i shut the car off i hit the button again so the radio can play if i wanted and i turn the screen off manually so it looks like it's not running then when i come back out to the car i push the start button again or the power button and everything lights right up and i go on my way i leave this like this all day for 12 or 14 hours until i shut it off for the night in my driveway then i redo this shit in the morning almost every day it'll make you think the cold seem something to do with it because it takes a lot longer when it's cold out there seems to be a signal or amplification problem that gets worse with age so seemingly like a built-in antenna some electronics that are just wearing out maybe the alarm system is the type that generates a new code every few seconds so thieves can't code grab and that's not happening something really weird is the only thing in my 09 that's a real problem the car has been perfect up until 11 months ago 13 months ago when all this started when i got the car the man only has one key fob it's silver on the back it's got the button below the steering wheel and it just weird in text stream all these people on here say i can kill the key fob and do all kinds of stuff i have a dealer tech stream computer and from what i can see i can do a whole lot of nothing to my key fob or i haven't figured it out yet now i walked out this morning and just pushed the button in my whole dash lit up just like it's supposed to very strange but we're also starting to get into the
     
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    wireless systems use transmitters and receiver systems....if the transmitter is verified to be working, well, that kind of narrows it down.....

    focusing on the lack of ability to open the doors with the fob (and assuming fobs and 12v battery are good):

    Your fob first 'speaks' with the 'door control receiver' which is located in the trunk area driverside (iirc). The 'door control reciever' then speaks to the certification ecu which is located under the dash directly in front of the steering wheel.

    There are also 5 oscillators located around the car for the sks system, but (I think) any of these failing would still allow the door locks to work via fob buttons. This is why I would start with the 'buttons not working' first, but I may be wrong. Been a while since I've played with these.
     
    #3 TMR-JWAP, Apr 6, 2022
    Last edited: Apr 6, 2022
  4. Tombukt2

    Tombukt2 Senior Member

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    I found these sensors in my gen too 2005 while just taking the car apart there's some of these things are buried i guess that's what these sensors are that i'm seeing they're on the four corners there's a tire pressure monitor sensor receiver transmitter with the megahertz or gigahertz stamped right into it i'm staring at one i thought maybe unplugging that they would stop trying to communicate to the TPMS monitors in the tires and turn the light off or something but of course not it just leaves the light on if i ever get to replace my dash that is one of the LEDs that will be removed
     
  5. mr_guy_mann

    mr_guy_mann Senior Member

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    A locksmith is all about locks- not diagnosing cars. A well equipped and capable locksmith would be able to replace lost key fobs (on a "working" car) and check if the fob puts out any signal when a button is pushed. Checking SKS functionality of the fob is going to be very specialized- not sure if dealers can do that.

    Diagnosing the car requires a shop with OE level scan tool and information. (Check all the ecu's for codes and follow the diagnostic procedure in the service manual). That would be a dealer or other shop - but many independent places won't work on hybrids.

    IF the problem is with both fobs then you need the OE Techstream scantool (or aftermarket equivalent)and a "seed" code to program (replacement) fobs to the car. The seed is generated by a server using a special ID number retrieved from the car. Again this is often dealer or a capable locksmith.

    Posted via the PriusChat mobile app.