Burning Smell and Prius Died - Is it Fried?

Discussion in 'Gen 2 Prius Main Forum' started by 90miler, Apr 11, 2021.

  1. 90miler

    90miler Member

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    Parked downhill talking to a friend in his driveway a couple of hours ago, with the car and A/C on. After maybe 15 min. I noticed a "burning electrical" smell. Since I would have been blocking his 1-car wide drive if it had died there, I said a hasty goodbye, and left, hoping whatever was hot would cool off once I got it back in the wind. But it went all dark and died a couple of miles up the road.

    For several months or more, there's been a situation with the power brake assist often seeming to not work right after or very soon after startup. A light & whistle would activate, but if I press the brake hard and/or shift back into park & wait maybe 10 - 15 seconds, it all goes back to normal & the brake assist works fine. The red BRAKE light stays on all the time now (at least before it died today) though, as does the ABS and I think CHECK ENGINE, tire pressure, & maybe another 1 or 2 lights -- but not the "red triangle of death" light. Also, the Multi-Function Display had gotten very dim during daytime, to the point of being almost unreadable. Has occurred to me I might need to check some battery voltages, but I haven't.

    I generally drive this car only on weekends & 2 or 3 times a year on vacations. So, as bad as this sounds to many of you, due to other priorities, I haven't given these issues the sort of prompt attention I should have. But, I need to figure this out. I realize I could be looking at anything from a charred cable connection to an inverter. The smell did seem to be coming from near or underneath the inverter. Any thoughts/tips on troubleshooting this are welcomed!
     
  2. ChapmanF

    ChapmanF Senior Member

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    The usual source of the fried-Prius smell is the little pump that circulates the coolant for the electronics in the inverter. It's not very hard to replace.

    When the pump goes into full fried-smell mode, it tends to eat the AM2 fuse in the fusebox, which does a pretty good job of making the car stationary. You can replace the fuse but the bad pump will just eat it again (while making more fragrant vapors), unless you unplug the pump first. Then you'll be able to put in a new fuse and drive (gently) to a shop or back home for the pump replacement. There's a conveniently-located connector for the pump near the fusebox itself where you can unplug it. Someone will probably post a photo.

    The brakes are a bigger job, but shouldn't be ignored forever (or, really, any longer).

    In general (you knew I was going to say this :)) it is better to attend to individual problems reasonably promptly when they crop up; that keeps you out of situations where the car's behavior suddenly deteriorates further and you've forgotten how many existing issues you're already ignoring.
     
  3. 90miler

    90miler Member

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    Thanks, ChapmanF. It does seem to make sense about the inverter coolant pump. In my previous (2008) Gen 2, which my youngest totaled for me, I replaced that pump myself and then Toyota replaced it again under the "recall". That's about where the smell seems to be coming from. I'll do as you say and try the fuse thing. And yes, guilty. I'll take my 10 lashings. Just a bit hard for me to get around to everything that needs doing right now. I hope a little surgery in a couple of weeks helps with that!
     
  4. 90miler

    90miler Member

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    ChapmanF, you were on the money! Checked the 15A AM2 fuse and sure enough, it was blown. Disconnected the pump harness up near the top of the fuse box and inverter, then replaced the blown fuse with a spare 15A which was stored right there in the fuse box. Pressed the START button and the Prius came to life again! Saved me a tow, as I had parked it yesterday in a small church parking lot about 5 miles from home. Now I can drive it home and shop for a new pump.

    When I bought my 2008 Gen 2 back in 2011 I had to pick it up in Houston and drive it back to Mobile, AL. Turned out the same pump was bad in it when I bought it. Drove it home in 40 - 50 mile hops between interstate highway rest areas, letting it cool down in between. It never melted down or blew a fuse, though. Replaced it myself then for about $130, with a pump from the dealership. I'll probably try eBay or Amazon this go around.

    Thank you!
     
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  5. 90miler

    90miler Member

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    Another thing I want to throw out here, though, is the MFD is still pretty dark. Just wondering if there could be a voltage problem somewhere which maybe even contributed to the pump failure. Don't know if there is, and don't know if that would cause it, but just thinking ....
     
  6. ChapmanF

    ChapmanF Senior Member

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    Got a voltmeter? Not hard to check....

    I've never thought of the MFD brightness as being much of a proxy for supply voltage though. Possibly more to do with temperature or the age of the MFD.

    Have you tried the adjustments on its Display screen?
     
  7. 90miler

    90miler Member

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    Yes, I hurriedly checked between the red positive post in the underhood fuse box and chassis ground, with vehicle off, before leaving for work this morning. Forget the exact reading but I think it was like 12.97 V. Don't know if that means the 12V battery is good, or if the hybrid system somehow covers for it if it isn't. I think in my previous Gen 2 I discovered that my 12V battery was only around 9 or 10V and the system had indeed been acting as a crutch for it. Guess I should disconnect a battery post and check it directly. I replaced the MFD touchscreen myself 4 years ago. It worked perfectly up until a day or two before the pump melted down. Then there has been the BRAKE light and whistle and delay, and all these other (seemingly) unrelated lights coming on.

    My wife has a BMW which progressively encountered several gremlins like this over time. The first things to go were some of the stereo speakers, and then the A/C fan would not go above a certain speed. Then, rear defog went out, and on and on. I had an independent "BMW mechanic" checking it out and he was stumped. Someone suggested replacing the battery. I scoffed at him, because the car was starting so briskly and dependably. Finally, I pulled the battery and had it tested, and was told it had the voltage but something like only 30% capacity. Replaced it and everything began working normally again. Researched a bit and found out the BMW was programmed to progressively shut down systems as the battery capacity went down. So, gotta wonder if that is a possibility here?
     
  8. ChapmanF

    ChapmanF Senior Member

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    As long as that's really with the vehicle off, that's very good. Nothing was covering for it; the hybrid system is out of the picture in any state except READY.
     
  9. 90miler

    90miler Member

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    Thanks. I think I will remove the 12V anyway and have it tested. I bought this car 4 years ago and have never had it checked. So, it can't hurt to know the status. It will also solidly eliminate this as a piece of the puzzle for any of my issues -- assuming it passes with flying colors. If it doesn't pass, well, that's definitely good to know, anyway.
     
  10. bisco

    bisco cookie crumbler

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    you can have the 12v load tested for free at an auto parts store. no need to remove it
     
  11. 90miler

    90miler Member

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    True. I was kinda thinking of digging into it anyway, at least enough to check the date on it and to verify condition of the post connections. I have noticed some corrosion from underneath the car -- a hole underneath the battery pocket. Maybe quarter sized. Looks like where one of the old lead-acid batteries leaked through. Don't know if I should be seeing this with an AGM battery.
     
  12. dolj

    dolj Senior Member

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    Just be sure the seller is a genuine Toyota parts seller. There are so many selling counterfeits (many just dropshipping from China) on those two sites. If the price seems too good, it probably counterfeit and will last a year, if you're lucky.
     
    #12 dolj, Apr 13, 2021
    Last edited: Apr 13, 2021
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  13. bisco

    bisco cookie crumbler

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    always a good idea. many find water there and in the spare tire sump.

    the hole may just be a drain with a missing rubber plug or grommet.
     
  14. edthefox5

    edthefox5 Senior Member

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    Don’t have to pull the battery to test it. Your one of the few that have a DVM.

    The battery measured higher than any g2 battery I have seen.
    Think the car was on.

    Simple test:

    Car off Measure at the front jump point. Write it down.

    Car off turn on the headlights in high beam. Measure it again. Write that down.

    Car off leave headlights high beam on for 5 minutes. At the end of 5 mins turn the headlights off wait 30 seconds and measure again.

    It’s a very benign test that any battery in good shape will not drop at all.
    If it drops a lot it’s suspect.

    what’s those 3 voltages?

    .
     
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  15. ChapmanF

    ChapmanF Senior Member

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    ... but at the same time lower than any DC/DC converter output I've ever seen in a Prius if it was in READY.

    Curious ....
     
  16. mr_guy_mann

    mr_guy_mann Active Member

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    Unless that was surface charge from recently turning off the car.

    Posted via the PriusChat mobile app.
     
  17. 90miler

    90miler Member

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    Car off Measure at the front jump point = 13.3V (Started off at 13.40V, kept trickling down to 13.25V before headlights turned on)
    Car off turn on the headlights in high beam = 12.53V
    Car off leave headlights high beam on for 5 minutes. At the end of 5 mins turn the headlights off wait 30 seconds = 13.03V
    Also, with ignition on (gasoline engine running or not) = 15.55V

    Checked a new Rayovac AA alkaline cell with my DVM, just for reference. It read 1.775V. Maybe DVM reads a bit hot.
     
  18. edthefox5

    edthefox5 Senior Member

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    Your DVM is reading 1 volt high.

    Extracting that 1 volt across your measurements the battery looks pretty good but
    I would buy a nice charger with recondition mode it will help that slight load loss on the high beam test. Its very good to put the charger on the battery every few months just to see how long it takes for the full charge light to come on. When they go south they go south fast its worth keeping an eye on it as when they start to go it takes forever to reach full then you know you have a suspect in the back hatch.

    Last thing you want is a dead 12 volt battery in this car.

    Never had a dead 12 volt in 14 years in my G2 it takes some proactivity.

    You need a new DVM. Its worthless if not accurate. Fluke.
     
  19. 90miler

    90miler Member

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    I replaced the one in the '08 Gen 2 at I think about 6 1/2 years old. It would only do about 10V I think. I try to always replace a conventional battery after 4 years before going into the next winter, 7 years for an AGM, whether they are still good or not. I know this one is at least 4 years old, since its been that long since I acquired it. I still plan to check the date on it. I know with the right kind of babying you can sometimes get more life out of them but to me it is just not worth waiting on that one cold night when you walk out to a parking lot to a dead battery.
     
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