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Parasitic battery drain?

Discussion in 'Gen 5 Prius Technical Discussion' started by Paul Gregory, Mar 10, 2024.

  1. Zeromus

    Zeromus Member

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    I'm laughing at the idea that, the lights turning on automatically in lower light conditions *while driving* is somehow as 12v drain. That's just asinine.
     
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  2. Approximate Pseudonym

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    The obvious explanation: when they can’t diagnose the issue, they have to first run out of ways to blame the customer before it can become an expensive and intractable warranty issue at Toyota’s expense.

    I hate that logic and I wish dealerships didn’t exist, but I also get it. If you look at cars that are mistreated by everyday driving, abuse by customers is almost the norm. Blaming misinformed customers must be a daily occurrence for a reason.

    But when you hear “you left the auto-lights on” as an excuse, there is something seriously wrong with the diagnostic process.

    On a related note, every car that has recently touched a local dealership service department in my area that I have driven has had overfilled tires and the auto-headlights turned completely off. These are multiple different local dealerships with the exact same practices. A bit odd.
     
    #62 Approximate Pseudonym, Mar 21, 2024
    Last edited: Mar 21, 2024
  3. HacksawMark

    HacksawMark Active Member

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    If local dealers ever treat me that way, I will return with the same problem enough times and then initiate a buyback under the states lemon law. I don't have any patience to deal with dealer incompetence.
     
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  4. Trollbait

    Trollbait It's a D&D thing

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    The auto lights off could simply be to keep the lights off while in the garage.
     
  5. Approximate Pseudonym

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    Yeah, I thought of that. If it were my shop, I would leave it on a safe default (auto-on or at least daytime running lights on) when sending it out the door to a customer, but these shops aren't detail-oriented.

    The high tire pressure thing is also probably to keep customers from coming back with low pressure notifications in cold conditions since most people don't touch their tires unless the TPMS warning comes on or something breaks. In many parts of Colorado, there are often wild daily/weekly temperature swings which make the tire pressures unstable. It still isn't safe or appropriate to send out cars at 45 psi when their factory recommended settings are in the low to mid 30s. Multiple dealers in my area do this.
     
  6. soft_r

    soft_r Junior Member

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    lol you guys just make up anything you want huh?

    It's just laziness. There's no reason to go 10-15 over stated PSI even with your "wild temperature swings". Just pull anything out of your nice person and spew it online I guess.
     
  7. Trollbait

    Trollbait It's a D&D thing

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    Laziness would be to simply not do anything beyond the immediate reason why the car was there. Why adjust the tire pressure if the car isn't there for a tire related reason?
     
  8. Approximate Pseudonym

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    Maybe you are misreading.

    I fill my tires to factory spec for a good balance of performance and tire wear. The dealership is the one overfilling the tires, presumably to avoid complaints from customers when the TPMS reports low pressure. Or maybe they are ignorant of the issue and not training their techs correctly. In which case, I would want them nowhere near my car.

    I am complaining about the dealership being lazy, since they should be educating customers on correct tire pressure instead of overfilling tires. Take another read of my posts.
     
    #68 Approximate Pseudonym, Mar 21, 2024
    Last edited: Mar 21, 2024
  9. soft_r

    soft_r Junior Member

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    No see, I was accurately stating an observation. That you just make up stuff, like this right here, because it sounds good in your head. But there is no real world scenario where this makes sense. Because why the heck would it need to be 50psi to ensure the tpms sensor doesn't go off due to temperature shift???? HOW DOES that make sense... you think it shifts THAT much?

    Car delivered with tire pressure at 50PSI | Alfa Romeo Giulia Forum



    It's all for shipping/storage purposes. Happens across multiple brands. And like some said, it just gets missed in the PDI. Over inflated tires are more susceptible to damage. The annoyance of having a buyer come in for TPMS in the winter (which almost never happens anyway because it's not set to go off with a small shift in pressure) is far less costly than tires that go out over inflated and get eaten by shitty roads. So now the dealership is on the hook for replacement costs since tire pressure was out of spec.

    All you have to do is NOT say the thing you aren't sure about. That's it and you help prevent rumors from spreading.
     
  10. KMO

    KMO Senior Member

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    Are you reading the thread or just making up anything you want yourself? This is talking about service departments, not new car delivery,

     
  11. Approximate Pseudonym

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    I am aware of new cars from dealer prep with overinflated tires. I was talking about freshly serviced cars with overinflated tires. I have driven freshly serviced cars that are at 40+ psi cold and should be 30-something. The service departments are definitely doing something wrong. They shouldn't be coming off the shop floor that way, but they certainly are. I didn't believe it, so I checked the computer and then verified with a tire gauge. You will find stories on internet forums reporting the same thing. This is multiple different cars I have owned (not just Toyota), and a Toyota dealership loaner in the past couple of weeks.

    I said I was speculating, but not without justification. I didn't make up the idea of mechanics intentionally over-inflating tires for questionable reasons like pleasing TPMS sensors, and others have come to this conclusion independently, as well.

    It's plausible based on what I have heard from one local tire shop. The shop owner was saying how the first cold day of the year had people coming to his shop asking why their TPMS warning lights are on. It's because they didn't maintain their tire pressure for half a year, and a sudden cold morning drops an already low tire pressure to a dangerously low tire pressure, and triggers a warning. So they go to the shop, and of course they could have saved the trip by understanding that a big temperature swing will change the cold pressure reading. There is definitely a lack customer education about this issue, and it just happens to be slightly more pronounced where I live.

    If dealerships don't do this near you, this could be specific to this altitude and climate of some parts of Colorado (you do know it's drastically different here from many parts of the country, right?). It gets extremely sunny here, and occasionally quite cold. I live above 6000 feet which means 3 psi less atmospheric pressure and significantly more sunlight. The temperature swings within a day can occasionally move tire pressure 3-4 psi cold, and within a week an even greater swing can trigger a TPMS warning for an already under-inflated tire. Colorado drivers also regularly might drive up and down mountain passes, which can be neutral for tire pressure, or can be quite a safety concern depending on the day. If it's different where you live, are you at sea level and do you have mild winters?

    When you consider that a typical driver on the road never checks their tire pressure, regular seasonal weather in Colorado can and does affect TPMS warnings. I don't personally find it to be an issue for my car, but I have been surprised at other cars that were slightly under-inflated and triggered warnings on a cold morning. I didn't think about this issue when I lived in a temperate sea level climate, but it can happen in Colorado with poorly maintained cars.
     
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  12. Mendel Leisk

    Mendel Leisk Senior Member

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    Here the reports were mostly hypermilers bringing their car to dealership with high pressure in tires, and dealership would lower to spec. Probably slightly lower than spec, since the tires weren't stone cold.
     
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  13. jo mo

    jo mo New Member

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    Sorry to hear about the headaches that have come from this purchase. Your point about the "integration with the Toyota app" has not been discussed much on this stream but may be one of many contributing factors. I am assuming the app integration from the car is powered by the 12V because I can see the status of charge, even when the car is not plugged in. The integration between the app and car is via the Toyota site and I have set this up using wifi at home so it is only in effect on my iOS device at home. I am guessing that it could also be via bluetooth so the remote and status functions are always active. I wouldn't think a continuous wifi/BT connection would be much of a drain but sometime continuous "re-connecting" attempts for communications protocols could be energy heavy. I know when my iPhone battery drains quickly when used in poor data/GPS coverage areas, when used on a motorcycle without a continuous source of power. If the problem returns after the new battery, as an easy test, you can opt out of all of the Toyota subscription services, which were provided with trial periods. Let us know how things progress, none of us want to have to go through this either. good luck
     
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  14. Approximate Pseudonym

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    Thanks!

    I agree that some testing of logging out of services might help if I have to diagnose similar problems again. It might be hard to diagnose since it will involve a lot of waiting to see if the conditions can be replicated or avoided while the car isn’t in use.

    However, so far, I’m around 400 miles on a fresh battery and it’s running great. I am pretty committed to the car as it’s been perfect except for that week in and out of the shop. If it turned out to be a failing battery all along instead of an electrically unsound lemon, I will be ecstatic.
     
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  15. jo mo

    jo mo New Member

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    We are all hoping it is just a bad battery and not some fundamental design flaw. I have only had mine for a few weeks and believe it is one of the smartest vehicle choices available, especially here in Canada with $5000 federal + up to $2000 Provincial rebates.
    Although the Korean offerings look appealing, not sure the reliability can match the 20 years of continuous improvement of the Toyota hybrids/plugins. Getting too old to having to deal with range anxiety that my friends with Tesla live with. Enjoy your car!
     
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  16. dreamer333

    dreamer333 Junior Member

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    We bought a 2024 Prius Prime XSE Premium March 14. When we drove out of the dealer’s lot, it had 3 miles on the odometer. It was manufactured in February 2024. On May 6, with 953 miles on it, when we were out of town, the 12V battery was dead after sitting for 2 days. We got a jumpstart from AAA, and drove it to the closest dealer (LA area) and, after 5 hours, were told the battery was fine. They gave us the usual recommendations, ie, limit 3rd party accessory use, avoid short trips, don’t leave plugged into AC, etc. We had already been following all the usual best-use procedures.

    Three hundred miles later, the battery was dead after sitting one day. After jumpstarting it, we took it to the dealer where we had purchased it. They ran tests for a day and said the battery failed, so they replaced it under warranty.

    Fast forward 3 weeks (and 400 miles) with no battery problems. This had us hoping the new battery was finally the fix we needed. We drove it 30-45 miles each day Wednesday and Thursday, getting home around 7 Thursday night. Friday morning it wouldn’t start. We tried using a 2 amp trickle charger, but it wouldn’t start all weekend. Monday AAA came out and jumpstarted it, but the ICE was making a noise we had never heard before. We had it towed to our local dealer again. They had it all day and gave us a rental car, then called at the end of the day saying it was fixed!

    It turns out they applied a software update (which one service advisor called a “recall.” Why that hadn’t been automatically updated we have no idea. Again it seems to have solved the problem, but, of course, we’re nervous that it will reoccur.

    We have had nothing but Prius for the past 17 years—a Gen 2, a Gen 3, and now this Gen 5. We have had 5 Toyotas in total, so know the value of the brand. Our confidence is now shaken with this experience. We do love the car and want to keep it, but it’s difficult to have a vehicle we can’t depend on.

    Has anyone else had a software update recently? If it is a new update, I guess time will tell if this will hopefully be the final solution!
     
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  17. Hammersmith

    Hammersmith Senior Member

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    The TSB* came out two days ago(10 June, 2024).

    T-SB-0054-24
    12V Auxiliary Battery Charge May Deplete When PHEV Charging Cable has an Extended Connection Without Charging


    *I'm assuming this TSB is what the previous poster's dealership was referring to. I'm not seeing any other TSBs or service campaigns related to 12V battery issues with 2023-24 Primes.
     

    Attached Files:

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  18. bisco

    bisco cookie crumbler

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    but it is happening to people who don't leave it plugged in. several here have mentioned getting a software update, i don't recall anyone coming back and reporting a problem after that.
     
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  19. dreamer333

    dreamer333 Junior Member

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    Back in March when we first got the car, we left it plugged in and used the scheduling to charge it every night, but after reading on PriusChat that it shouldn’t be left plugged in, we started only plugging it in to charge for an hour or two.

    We didn’t have a battery problem until May, long after we stopped leaving it plugged in. BTW, we had an EV ten years ago that we did keep plugged in and charged on a nightly schedule after midnight when we had lower EV rates, so we were used to that routine, which was much more convenient than having to monitor the charging time.
     
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  20. douglasjre

    douglasjre Senior Member

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    Charge batt and do load test w old fashioned tester. Use the kind that puts a true load, not the kind that approximates internal wear by testing internal resistance. If batt good, do parasitic draw test. "Eric the Car Guy" does a fine job explaining how on youtube