Killswitch: Best Practice for Manually Immobilising a Prius C?

Discussion in 'Prius c Technical Discussion' started by Sky_Velleity, Dec 3, 2019.

  1. Sky_Velleity

    Sky_Velleity New Member

    Joined:
    Jun 2, 2019
    14
    9
    0
    Location:
    Canberra, Australia
    Vehicle:
    2017 Aqua
    Model:
    N/A
    Hi all,
    While my intents are modification, I’d like to discuss the technical side of this issue before I break out the angle grinder and soldering iron.

    I’ve been trying to think of the best way to safely disable my Aqua, and would like to discuss the possible options.
    We’re assuming, for sake of argument, that someone has stolen or cloned my key fob, and the car would normally allow them to drive off, however my own security system is installed; what is the best way to stop them?

    I’l like to have a chat about this before I go for another techstream subscription to work out the finer details, but should that be my best option, it won’t be the first time. (What I’d do for a deadtree version of all the documents... or just a really large PDF.)


    I digress.
    For traditional vehicles, I’ve seen people put a relay on the line to their fuel pump, so that if they do not enable it before driving off, the car will not get very far, if even start at all. Additionally, should the car be disabled while driving, it would stall, and allow the driver/thief to come to a safe stop, hopefully. This is not something I would hope to do, as my intended system would be disabled by default, needing activation before the car drives off, but it’s worth considering as if anything were to happen and the system were to trigger while the car was driving, I would not want it to risk injury or damage.

    As for my Aqua, I have identified multiple potential options, and would like to explore them.

    1: Fuel pump
    Same as before, but now with the added benefit that the car could drive some distance on electric, should the system be engaged while the car is moving.
    Problem is, someone could still drive the car a fair distance on electric from parked with it engaged. Perhaps an option for a safe, post-theft remote killswitch, as even if it is activated while the car is driving, the car would still be safely controllable, as I have done many times when pushing my luck with its range a little too far.

    2: Contactor
    With a line to the contactor cut, the car’s not doing anything if the Power-on-self-test fails, let alone not having the HV battery itself.
    Con is, I’m not sure how happy the ECU’s and inverter would be if the test failed, and how much work it’d be to get them working again.
    Good for a one-off, but needing to get it towed to a dealer after just one test would be unfortunate.
    Additionally, I suspect that cutting the contactor with the car still driving could do untold damage to the battery, contactor, and inverter. Oh, and probably kill someone

    3: 12v line
    Problems all around here, the least of which is that a thief may think the car is just flat and try to jump it, mixed with the car needing to be re-enabled before the key would unlock it, throw in the damage done if disabled while driving (unless the car can sustain itself from the 100A output on the inverter, still, if not, getting teleported into a T-model ford, while doing 100MPH, with no airbags or power steering etc, that’s not a wreck I’d want to buy), and, worst of all, having to reset the clock every time I get inside.

    4: Some super secrit control line somewhere that Toyota installed for just such an occasion
    What can I say, I’m an optimist

    I’ve had a poke around the forum and haven’t found any similar discussions yet, but I might not know the right words to search for.
    “Killswitch” doesn’t turn up much, spare a thread where I found the following:
    After which, the thread died.
    Another post suggested
    and while I don’t totally understand the meaning of this, I’m guessing it means to cut a line to something so that the car’s power-on-self-test will fail, and the car will not enter READY mode.
    Let the car itself handle the locking.

    Many such options, the only question now is to find one that would not cause a permanent error code if the car was started without it.
    Additionally, it would mean that, if it’s something as innocuous as, say, one side of your headlights, that should it be disabled while the car is in motion, nothing detrimental should happen.
    A jumper for an optional feature that was not installed, perhaps?

    Anyway, I’m out of ideas, and would be very grateful for any further commentary.
    Thanks in advance, and all the best
    -Sky
     
  2. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

    Joined:
    Oct 17, 2010
    37,138
    25,942
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    I think once you get the bit-in-your-teeth, it's very hard to let go. Still, two words?

    Cargo cult.

    If someone really wants your car, I'm guessing they'll just drag it up onto a flat bed truck. Or lift the front and back wheels on dollies (dollies surplus to requirements if parking brake not solidly set).
     
  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
    May 12, 2018
    2,847
    2,656
    1
    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    That one looks straightforward, if your car has pushbutton start. Not all Aqua/Prius c trims do.

    By isolating the brake pedal switch with a killswitch, the car could not go into ready until the killswitch were closed.

    That means the brake lights would also be inoperative while parked, and they could be accidentally disabled while operating by opening the killswitch. That could have consequences, especially in combination with cruise control usage.
     
  4. Sky_Velleity

    Sky_Velleity New Member

    Joined:
    Jun 2, 2019
    14
    9
    0
    Location:
    Canberra, Australia
    Vehicle:
    2017 Aqua
    Model:
    N/A
    I have more than enough contingencies for if they lift the thing and pull it, still, unless they put it in a totally soundproof faraday cage, I’m finding it. Everyone inside or around the car would be permanently deafened, everyone even remotely close would be calling the police, and there’s enough GPS trackers and transponders inside that unless they melted it down into homogeneous slag, I’m finding it.
    The point is, I would be able to find it long before they had the chance.
    This thread is simply so I can avoid all such contingencies, rendering them irrelevant. I won’t go into further detail as I don’t wish to provide any information usable to circumvent any of my security measures.
    Just because it is a possibility that someone with a UFO can fly over my house and teleport my car into a volcano doesn’t mean we should all bend over backwards and do nothing to secure our belongings.
    I’ve got the damn thing insured for enough to import two brand new Aqua’s fresh from Japan, that’s besides the point. Some things have sentimental value, that you can’t insure, and for that reason I’m going to give anyone who so much as looks at my car funny a permanent case of tinnitus.
    For some of us, it’s not a matter of a cost benefit analysis. It’s “Did I do everything I could, reasonable or not, to secure my car, allow myself to recover my car if the thief had a flatbed, and, if they did have a magic volcano-teleporting UFO, at least deafen them for their trouble?”
    If I don’t at least make someone permanently reconsider their life of crime, was any of it even worth it?

    I will also add that individual Aquas have been used to transport goods, the theft of which exceed the combined value of every Aqua ever produced, and that people who work for certain agencies would find the notion of any level of avoidable risk being “acceptable”, well, rather aggravating.
    Aquas are nice cars. They’re small. Quiet. Discrete. Innocuous.
    That may attract a certain type of person.

    Finally, $80,000 of repairs on a single car.
    You don’t need to tell me I’m crazy. You won’t be the first, and there’s nothing you can say to convince me. You can’t convince someone there’s something wrong with them when they already believe and accept there is.

    Mine happens to be pushbutton, out of curiosity I’ll see how well the handbrake does at stopping it on the freeway with the engine still cruising. Drum brakes are cheap, right?
    A major concern would be the lack of a failsafe option here. Either require a relay to be engaged to cut the brakes, using power when the car is off, and defeatable by cutting power to the security module, or have the brakes cut when the power is not applied, and thus risk loosing the brakes if the module fails, or power is cut in any path of the circuit. Neither options seem acceptable to me.
     
    Mendel Leisk likes this.
  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
    May 12, 2018
    2,847
    2,656
    1
    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    Understand that you aren't losing the brakes; you're losing the direct electrical signal used to trigger the stop lamps on the back of the car. The same signal is monitored by the cruise control as a cancel/cut.

    You would always have brakes- but you might have cruise control fighting back unless you gave it an explicit cancel through the stalk control.

    You could theoretically do a latching relay to bypass around the killswitch until the next startup. That actually doesn't sound too hard.
     
  6. Sky_Velleity

    Sky_Velleity New Member

    Joined:
    Jun 2, 2019
    14
    9
    0
    Location:
    Canberra, Australia
    Vehicle:
    2017 Aqua
    Model:
    N/A
    Ah, a latching relay may be a rather safe way of doing things, there’s plenty of signals that correlate to the car being in READY so holding the latch open with one of them would be trivial.

    I believed the car’s regenerative braking was controlled by a position sensor on the brake pedal, and that the car controlled the brake lights and cruise control, along with going into READY, from this signal should it be partially engaged. If this isn’t the case, or there are multiple signals, then that clears all my worries, but at very least I remembered that you’d still have the hydraulic brakes anyway, electrical signals or not.

    Between this and the idea for a latching relay, I’m pretty happy with this as a killswitch. If the worst possible thing that could happen in a failure is them loosing the brake lights, that seems pretty good to me.

    Edit: Looking at the schematic now, it does appear there is a seperate switch for the brakelight, the only question left is if that is used for READY, or the position sensor. Time to test it.
    If it is just the switch used, and the switch directly controls the lights, with the ECU detecting a signal, then it’s still possible to cut the line to the ECU without cutting the power to the lights itself. I’ll have to check the wiring diagram...
     
  7. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

    Joined:
    Oct 17, 2010
    37,138
    25,942
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Faraday cages are not soundproof, as far as I know. Just sayin' :ROFLMAO:

    No, all the more power to you, I've gone down that road with a few vehicles, decades back.
     
    Sky_Velleity likes this.
  8. Sky_Velleity

    Sky_Velleity New Member

    Joined:
    Jun 2, 2019
    14
    9
    0
    Location:
    Canberra, Australia
    Vehicle:
    2017 Aqua
    Model:
    N/A
    I was suggesting you’d need something to be both a faraday cage and soundproof, just to be sure.
    If any frequencies are getting out, I’m finding it.

    There’s certain mistakes in life that you just have to make. It’d be a mistake not to.
    I’ve promised not to get too attached to any of my new cars, but they’re all replaceable. This was my first.
    Half the point of insurance is to give me something nice and fancy to distract me from what I’ve lost. Really cut down on the grieving stage. It’s hard to be too sad when you’re on a tropical island sipping glasses of “well if you can sort out the problem with the power steering then power to ya”, while crying tears of “why didn’t I just accept the writeoff payout the first time?” while waiting for a new car to be built.
    At this point I’m not even sure if I care about the car as much as I’m making it out to be, but trying to make it as unstealable as possible has become somewhat fun.
     
    bisco and Mendel Leisk like this.
  9. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    2,488
    1,120
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    The fact that you are spending more than 10 seconds considering this idea does not exactly qualify you as an "optimist" in my opinioin.
    :whistle:

    And the thread should have died; this one too.

    The potential problems FAR outweigh any perceived benefit.
     
  10. Sky_Velleity

    Sky_Velleity New Member

    Joined:
    Jun 2, 2019
    14
    9
    0
    Location:
    Canberra, Australia
    Vehicle:
    2017 Aqua
    Model:
    N/A
    Considering this thread resolved any and all potential problems I have come across thus far, and the only thing left for me to do is play around with some relays then wire them in to one of my tracking modules, I don’t see what potential problems remain at all.
    I live in the car theft capital of my country. Every day I see a new burned out car on the side of the road.
    Finding and importing a 2015-2017 Aqua, in the trim and colour I like, in mint condition, takes more time in paperwork than I’ve spent on my security system thusfar.
    I’m an optimist, in that “If the worst possible thing happens, I’d expect something other than the worst possible outcome, as both the worst possible thing happening, followed by the worst of all possible outcomes afterwards, seems rather unlikely”.
    If I make sure the worst possible outcome isn’t that bad, then I’d never need to worry a day in my life.

    The benefit is that if someone tries to steal my car, they most likely will either give up when it doesn’t start, or abandon the idea when the 160db alarm doesn’t stop after they disconnect the battery, rather than me having to grab my [redacted]s, chase them through town with my [redacted], eventually [redacted], dragging them out of the wreck, and [redacted] out of them, then having to explain to my insurer what happened. Again.
    Having to do so would be most unbecoming of me. I’d really rather not, if it’s all the same with you.
     
  11. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    2,488
    1,120
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    OK, you got me.
    My perspective is: It's JUST a car. And that is what insurance is for.
    I tend to forget almost everybody has some kind of obsession that they need to feed.
    Good luck.
     
  12. Sky_Velleity

    Sky_Velleity New Member

    Joined:
    Jun 2, 2019
    14
    9
    0
    Location:
    Canberra, Australia
    Vehicle:
    2017 Aqua
    Model:
    N/A
    Oh I have far more than just the one.
    Still, if we’re going to moralise then I’d suggest you don’t just drop into random threads and offer virtually no advice. You mentioned problems with what’s been discussed, care to offer anything further? Actually tell me why a killswitch, something that’s been installed on cars dating back decades, is somehow all of a sudden a bad idea?

    If not, then I’m curious why you’re here.
    “Spending months wages, tens of thousands of dollars, possibly a thousand hours of labour, on a car? Perfectly reasonable. No issue.
    Spending a WHOLE WEEKEND putting some trackers in it? Protecting your property rights? WoooOooOoOoAAAh, looks like someone’s a little obsessed xdxd ”
    Such comments are completely without substance and are utterly vapid and meaningless.
    Either someone cannot afford premium insurance and as such may not be able to afford the luxury of unprotective property rights, or someone can afford insurance however still believes, on principle alone, that property rights should be protected. To suggest such things are an “obsession” that someone needs to “feed” contributes about as much good to the world as going to an up market restaurant, sitting down for a meal, and spending the entire evening lecturing the people sitting on the table next to you about world hunger.
    Or going to a forum for the owners of exotic and luxury sports cars and calling them all obsessed.
    89% of people aged 21 to 35 state that their lives have no meaning, and, coincidentally, the suicide rate for that age bracket is skyrocketing, driving down life expectancies for entire nations.
    When things like “Property Rights” and “Hobbies”, “Pride in your Possessions” and the like are universally derided, in a society where someone cannot be expected to maintain ownership of something when someone else may wish for it more, when society is on its last legs, barely hanging on by a thread because at least maybe people will still want to go to work to buy fancy shiny things, and you start hacking away at the concept of property rights with a chainsaw, where do you expect the world to go from here?
    How much of the year am I supposed to be driving a filthy hire car before it’s justifiable for me to spend a weekend trying to prevent my car from being stolen?
    You get the society you deserve.
    When you treat crime as something rare enough that it’s worth putting something simple like a killswitch on your car, just in case, then criminal activity is disincentivised. When you treat is as something so commonplace that it’s not even worth trying to reduce your chance of being stolen from, and your only consideration is for a contingency after the fact, then by doing nothing to disincentivise crime, you encourage it.
    I’d rather not live in a society like that.
    Some maybe happy living in a world without property rights, freedom from crime, individual freedom, rights, personal responsibility, but I’m starting to get a taste of that world, and I do not particularly like it. I am more than willing to fight it. One small step at a time.
    And pray tell, if not for hobbies, what the hell else am I supposed to do with my time?
    There is little anything anyone in the world can personally produce that cannot be produced elsewhere more cost-effectively. Am I just supposed to consume? Is that it?
    Don’t change or create anything, just buy car let car get stolen then buy new car, so long as I never stop consooming, never create anything, never question the idea that everything you can purchase is already the best that something can possibly be, just buy new thing when new one comes out, it’ll have the things that the deranged, obsessive losers added five years ago! Just consoooooooooooooom!

    Again, I’d rather not.
     
  13. smilyme

    smilyme Member

    Joined:
    Nov 3, 2019
    112
    34
    0
    Location:
    Canada
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Consider the "range sensor" it reports PRND to transmission ecu
    Use common


    I have never tried this on prius or any hybrid.
    Do hybrids "start/turn on" the electric part if not in P or N ?
     
    #13 smilyme, Dec 3, 2019
    Last edited: Dec 4, 2019
  14. sam spade 2

    sam spade 2 Senior Member

    Joined:
    Mar 31, 2018
    2,488
    1,120
    0
    Location:
    USA
    Vehicle:
    2017 Prius c
    Model:
    Four
    YOU need to lighten up a bit, sir.
    This is a DISCUSSION forum. It is not a "serve your every need" resource.

    It seems to me that there are a LOT of relatively simple ways to accomplish your goal.......like a battery disconnect "bar" like is used on the HV battery only installed on the 12 V. And what happens if you pull the HV safety plug and try to start the car ??

    There certainly should be more than one fuse that you can pull that will disable the car but not the entry system.
    A switched line could be put on that fuse.

    But I certainly will NOT be giving you any good advice........because you probably won't be able to recognize the worth of it while you are ranting.

    Good luck.
     
  15. Royston.K

    Royston.K Junior Member

    Joined:
    Apr 18, 2019
    73
    50
    0
    Location:
    Singapore
    Vehicle:
    2012 Prius c
    Model:
    N/A
    Disconnect the HV battery buiild a relay/switch on this line. Vehicle won't be able to move even if started. By cutting off fuel pump the vehicle can see be driven if there's sufficient fuel primed in the lines.
     
Loading...
Similar Threads - Killswitch Best Practice
  1. Bigboi
    Replies:
    7
    Views:
    2,737