My Prius won't turn off — no, I mean it *REALLY* won't turn off

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Gwyneth, Jan 14, 2022.

  1. Gwyneth

    Gwyneth Junior Member

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    OK, so there have been approximately 4 times in the past 6 months or so when I've had problems either turning my 2004 Prius off and/or the dashboard, after the car was turned on, was black. I'm assuming that this is due to a faulty combination meter, and I really was planning on sending mine out for an exchange.

    In the past, when the car wouldn't turn off or the dash was blacked out, I found that turning the lights on and off 3 times while holding the Info button down fixed the problem. Today, however, not so much.

    My car is now sitting in my driveway with the motor still going. I've done the usual 3x light/info button protocol literally dozens of times, but it's not working. And, in fact, this time it gave me a different screen than usual that I can't even get out of (and perhaps this is the reason why my usual lights/info button system isn't working?).

    Currently, my MFD shows the Diagnostics Menu screen. There doesn't seem to be any way to back out of this menu. When I do the info button/3x lights protocol from this screen, it brings me to the Product diagnostics menu screen. I've tried everything I can think of, and I can't get out of the Diagnostics Menu.

    I drove the car home after I discovered that I couldn't turn it off, which was about 35 miles (it was an interesting drive, given that I had no speedometer and there are known speedtraps on the highway I had to take). I was hoping that maybe the drive would jiggle things on the combination meter so that I'd be able to turn the car off. Alas, no luck.

    So here are my questions: Does anyone have any suggestions as to how I might shut the car off? Barring that, can I remove the combination meter while the car is still running? It's Friday night, and there's not even a mechanic in my small town that I can contact until Monday. (I think I have about a half a tank of gas; I guess I could just keep the car running all weekend.)

    Thanks in advance for any help!
     
  2. JohnPrius3005

    JohnPrius3005 Member

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    Have you tried holding the power button for a long time?

    Have you tried pulling the electronic key out of the dash?
     
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  3. SFO

    SFO Senior Member

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    Unless DIY, you will find a quality rebuilt from Matt ( @Texas Hybrid Batteries ) : Prius Speedometer Replacement

    Disconnect the 12v in the back right corner of the trunk, easiest way would be to disconnect the large white plug closest to the front of the vehicle (12v positive terminal) be sure to place a towel or rag between the hatch and latch so as to prevent the rear deck from closing. If you can't leave the vehicle unlocked, then lay the back seat flat and so that you can crawl into the rear area to reconnect the 12v later.

    Reconnect the 12v when you need to start the vehicle, and it will take two (2) attempts before it actually starts upon reconnecting.

    [​IMG]
     
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  4. Elektroingenieur

    Elektroingenieur Senior Member

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    Is disconnecting connector F15 (seen in your photo) always enough? In the Emergency Response Guide (PDF), on page 16, Toyota suggests also removing the HEV fuse under the hood, presumably because the 12-volt bus might still be energized by the DC-DC converter if the hybrid system is running.
     
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  5. SFO

    SFO Senior Member

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    Guess we might find out, or she might run out of gas first.

    Question, can you stop the engine from running by disconnecting the "dome fuse" ?
     
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  6. Elektroingenieur

    Elektroingenieur Senior Member

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    Just to avoid confusion, if the problem discussed in this thread is the typical one, described on Luscious Garage’s page and in many previous PriusChat threads, it shouldn’t be necessary to disconnect anything or remove fuses: as @JohnPrius3005 kindly mentioned, a long press on the power button is ordinarily enough to get the power source control ECU to turn off the power.
    Removing the DOME fuse would prevent the hybrid system from being started, since it controls the +B1 power supply to the smart key ECU, but I’m not sure what the effect would be if the hybrid system were already running.
     
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  7. Gwyneth

    Gwyneth Junior Member

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    Yes, once I realized that I couldn't turn it off the "usual" way (i.e., Info button + lights on and off 3 times), I tried holding the power button for a long time. When that didn't work, I tried holding it again, this time for a long time. Then, I vaguely remembered reading when this first happened that hitting the power button three times in quick succession sometimes worked but you might have to do it more than once, so I tried that a half dozen times. Then I held the power button again for a long time (a couple of minutes at least). then I went back to the Info button + lights for a while.

    I didn't take the fob out of the dash, as I've never put it in it, as I have a smart key system.

    Thank you for these suggestions. They're all good ones.
     
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  8. Gwyneth

    Gwyneth Junior Member

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    UPDATE: I got the car turned off!

    After writing my original question, while waiting for the mod's OK for it to post, I decided that since the car was already running, I might as well drop off some books at the library. (I wasn't sure how long my gas would really last, so I figured I might as well do it now.) The road to the library, while not long, is pretty curvy, which may factor into this. Anyway, I got there and automatically, by habit, pushed the buttons to turn it off — and it turned off! When I realized what had happened, I turned it back on, then turned it back off, and it worked again!

    After I dropped my books off, I started the car up again, then turned it off. All good (with one minor exception that I'll get to in a moment.) A couple more on's and off's, then I drove back home. So it seems like that problem has solved itself.

    Did the curvy road jiggle a capacitor into a sort-of correct place. Or maybe it was just fate. I'll never know.

    Here's the minor exception: At no time during any of this did my dash lights come back on; I still have no speed, mileage, fuel gauge, etc. But at least the car's not idling in my driveway until it runs out of gas, so yay for that.

    I'm assuming that this is still a combo meter problem, and I need to get one immediately. However, if any of you think it might be something else, please let me know. I'd really appreciate it!
     
  9. Gwyneth

    Gwyneth Junior Member

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    Yes, I'd read that before, that one long press of the power button is enough to turn the car off. Alas, that has never worked for me on any of the times this has happened.

    The only thing that's ever worked has been pressing the Info button at the same time that I turn the lights on and off 3 times.

    The reason that SFO suggested disconnecting the 12v battery was because nothing else was working to turn the car off. It was the solution of last resort.
     
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  10. Gwyneth

    Gwyneth Junior Member

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    Thank you for your very valuable, very detailed info. I didn't need this info tonight, fortunately, but there's an excellent chance that I may need it before my new combo meter arrives. So, again, thanks!
     
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  11. JohnPrius3005

    JohnPrius3005 Member

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    Hi Gwyneth, congratulations on doing what you did. You’re also quite courageous for going on the little trip you did and for turning your car off and on multiple times, knowing it was not certain to stop or start again.

    I am certainly no expert. But I do have 3 Priuses that have similar, and other problems. I keep them limping along and have done so for a few years.

    For what it’s worth here is some of what I do and my thoughts.

    Turning the lights off and on and holding the info button is no secret solution. It likely changes some level of electric volts or amps just enough to get a failed/failing component to work. But if it works then it works.

    Your power button may be suspect but changing that is just throwing parts at the problem. So far I haven’t done that, but apparently it’s a lot easier than changing the combo meter.

    Ditto with the 12 v bat. You will certainly get advice to change the 12 v bat. This has not worked for me. It may for you.

    In my case my 12v bat discharges easily. I deal with this by disconnecting the big white plug to the battery every single time I power my car off! This has involved filing down the clips/latches of this white plug because it’s pretty hard to remove. Also making sure the mechanical key unlocks a front door.
    And the back seat backs are folded down to allow access to plug the white plug back in. At home I prevent the “trunk” hatch back door from latching and always put a charger on the battery.

    in addition my HV “big” batteries are also problematic so I’ve built cheap grid chargers and wired them in and charge the HV batteries overnight from time to time.

    All of this is still I think easier than changing the combo meter! Although I may be wrong about this. And I doubt the combo meter is the cure.

    It is possible to fix these problems and others with Priuses, but it’s not easy. Many here are far better at it than I am.

    Another thing I do is have multiple vehicles although that too has failed me.

    You will and have learned a lot dealing with your old car.

    Good luck. A lot of smart highly experienced people on here know as much or more than the most highly trained Toyota Prius techs. And if you’re really lucky you may have access where you live to a good independent tech. But be skeptical. Confidence is no real substitute for real knowledge and skill!
     
  12. ChapmanF

    ChapmanF Senior Member

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    As suggested upthread, the real, best, only solution is to fix that combination meter before the shenanigans get too much more inconvenient than they already are.

    As Elektroingenieur pointed out upthread also, knowing how to disconnect the 12 volt battery in back is useful information for a lot of purposes, such as if you want to keep the car from starting, but might be of little use when the car is already in READY mode and producing its own 12 volts. My Gen 1 would never miss a beat if I disconnected the 12 volt battery while it was running; that was my typical procedure when offering jumps to other cars.

    I think you'd probably get the car pretty much off eventually if you popped the hood and started pulling on fuses with names like HEV, AM2, and EFI, or under the dash with names like ECU-IG and IGN. Once the READY light dropped out (if you can even tell that on a flaky combo meter), it would no longer be making its own power, and you could disconnect the 12 volt battery in back and it would be well and truly off.

    I wouldn't be too surprised if you reconnect the battery and fuses and it tries to turn on again. I think I've noticed that after a sudden power loss, it tries to return to the state it last remembers instead of just waking up and being off.
     
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  13. JohnPrius3005

    JohnPrius3005 Member

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    Hi Chap, As I think you know, you are one of the very smartest and most helpful people on here and I've learned a great deal from you, and others could do a lot worse than to paying close attention to your posts. Thank you for your generosity.

    Do I understand correctly that a failed or failing combination meter can cause a lot of hybrid problems, and is not simply a "nuisance" of having no display? If that is so, I'd better get good at replacing or repairing my combo meters.

    Aloha
     
  14. ChapmanF

    ChapmanF Senior Member

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    One of the biggest nuisances associated with the combo meter failure, in a lot of threads here, is the eventual inability to turn the car off, which can become a pretty big nuisance.
     
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  15. JohnPrius3005

    JohnPrius3005 Member

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    Thanks!
     
  16. Aegean

    Aegean Active Member

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    Do not forget that when the car does not turn off while the combination meter is defective many times the trunk does not open as well. Then you need to crawl in the trunk from inside and open it to access the battery white connector.
     
  17. T1 Terry

    T1 Terry Active Member

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    We have a very well travelled '08 Prius that often looses it's combo meter and the hard to turn off problem. So far it eventually turns off, but we found combining a turn signal switched on often helps with the no turning off and being able to get the combo meter back on with the info light flash fix .... or undoing the cable under the red cover under the fuse box near the left hand headlight. The rear hatch does open once you get the car turned off when the combo meter fails.
    We found an app on the smart phone to give us a speedo when the meter decides to play silly buggers so that gets us through that problem.
    We also discovered the odometer doesn't record when the combo meter fails to light up and that really messes with the ltr/100km measurement and the expected 700km from each tank of fuel .... and the low fuel warning doesn't go off either, so a few panics as to just how much fuel we actually have left in the tank can occur .... so we've ended up also carrying a 4 ltr petrol can if we are travelling the 200km round trip to Adelaide and back to Mannum.
    We paid very little for the Prius in the first place, it has cost us a catalytic inverter, tyres, oil and fuel over the last 40 something thousand kms, we want to see if it will keep going till we roll up the 1,000,000km on the odometer, so we don't want to replace the combo meter because we will loose that 740,000+ km reading we have now.
    It is a reliable workhorse and we love it, so we just put up with it's few strange habits :lol:

    T1 Terry
     
  18. ChapmanF

    ChapmanF Senior Member

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    Another option is to replace the fractional-dollar capacitor in the combination meter.

    This kind of intermittent issue makes a great psychology experiment; all the threads that talk about it demonstrate the incredible variety of interesting dances people come up with and can convince themselves are helping, as long as sometimes the car works when they do them.
     
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  19. T1 Terry

    T1 Terry Active Member

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    A photo and arrow where the faulty device is located would be helpful ;) a part number for the replacement part would also help lots :lol: I figured it might have been a resistor no longer draining a diode rather than the diode itself .... but I really didn't want to remove the combo meter and have a play with it in the hope I stumbled on the faulty part ..... I have enough to do repairing failed 24/240vac inverter/chargers/MPPT controllers to satisfy my curiosity for circuit board tracing :rolleyes: plus trying to repower this early model electric car I bought a while back, a Blade Electron V
    the one in the video is the same model as I bought and was originally owned by Ross Blade himself and in immaculate condition.

    T1 Terry
     
  20. mr_guy_mann

    mr_guy_mann Senior Member

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    Ummm, if you go to the top of this (Care and Maintenance) forum, you'll find the "sticky" posts. Fourth one down is "combination meter repair- DIY". Read that- it has the procedures and pictures in it, and somewhere has the part numbers from DigiKey for new capacitors.

    Posted via the PriusChat mobile app.
     
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