Is my inverter coolant pump slowly failing?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Kehaunani, Oct 14, 2017.

  1. Kehaunani

    Kehaunani New Member

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    was2007 Gen 2, 80k miles.

    Background info: Twice recently, when driving to town in the afternoon heat (nearest town is usually about 15 degrees hotter from my home/work), I will park my car, come back to it and restart, and get the triangle exclamation point on dash with the car exclamation on the mfd.

    First time I drove about a 1/4 mile to the dealer, but they can't diagnose my car for 3 weeks. While in the shade at the dealer, light goes off. Dealer says probably just a computer malfunction. I noticed my oil was very low, so I topped it off, drove home, no more warning lights for weeks, figured it was the oil and didn't end up going to that appointment.

    Same lights under same driving conditions again about a month later. Checked oil level, it was fine. By the time I got home, car rested overnight in much cooler weather, no more warning light. Borrowed friend's OBD scanner and no codes stored. Spent hours reading priuschat.

    1. Checked my 12v battery via MFD: reads 12v exact in ACC mode after car sat overnight. Note this batt was replaced exactly 5 yrs ago. Hybrid battery replaced about a year ago. Most days of the week I only travel to/from work about 2 miles apart.
    2. Checked my oil level, which is fine since the last top off a few weeks earlier. Did full oil & filter change anyhow since it was overdue.
    3. Checked inverter coolant pump. Last replaced under recall in Dec 2010 at 35k. In IG-ON pump sounds like aquarium pump as described, but coolant reservoir has very little movement. From youtube videos, I see that movement should be more vigorous.

    Is it possible that the pump is slowly failing? Or is it always a complete failure, and my pump is fine? Is that 12v battery reading above not normal?

    I need to drive a couple of hours to another hotter climate this weekend, and am afraid of burning the inverter on such a long trip. Looking for advice, since dealer does not have availablity til next month (I'm rural so no other dealer options).
     
  2. WilDavis

    WilDavis Senior Member

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    There should be movement in the coolant reservoir, not a gushing, but a definite swirl, I find the best way to check is to carefully remove the cap, and shine a flashlight in and take a peek! Good luck, and welcome to PriusChat! ;)

    Edit: When the system is in "Ready" (of course! :rolleyes:)
     
    #2 WilDavis, Oct 14, 2017
    Last edited: Oct 14, 2017
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  3. 05PreeUs

    05PreeUs Senior Member

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    Possible? Absolutely.

    Without reading the codes stored in the various computers in your car, replacing the pump would be unwise. At the age and climate, the HV battery may also be to blame. That is why it is important to get all the clues the car has to offer before jumping to a repair.
     
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  4. Kehaunani

    Kehaunani New Member

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    Thank you both so much. The HV battery was replaced about 15 months ago. Agree on not replacing the pump unless needed. Really not much choice but to drive this car to and from a couple of appointments, since one of them is a tire install. Will take an OBD reader with me at all times in case the lights pop up again. Will also keep that dealer appointment this time.
     
  5. exstudent

    exstudent Senior Member

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    IMO, inverter pump produces fluid movement equivalent to a very gentle stream. Some like to describe the fluid movement as "turbulence," which to me entails white water rapids.

    You hear the inverter pump and see fluid movement, albeit it's weak by your stadards. It is working IMO. the dealer should have retrieved some stored codes, even w/ the light off.

    You can always replace any wear part (ie inverter pump) premptively, to minimize unwanted breakdowns. These pumps seem to last a LONG time, 100K+ miles. For ypur peace of mind, you may want to just replace the inverter pump.

    Test health of 12V batt again w/ a greater load.
    1) Let car sit overnight again.
    2) Foot off break, press Start twice: IG-ON mode.
    3) Headlights on HIGH
    4) Vent fan on high, AC off
    5) Radio on, low volume.
    What reading do you get?

    12V in ACC mode is light. I bet you'll have a lower reading in IG-ON, with lots of things on.

    4-6 years seems to be the unofficial range people get. Some get longer. Consider getting a smart AGM capable charger. You can always do a periodic maintenance recharge to ensure your 12V batt is fully charged, to get as much life as possible.

    I remember one person here has a very aggressive and premptively approach to 12V batt: always replaces when the batt is 4 years old.
     
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  6. Kehaunani

    Kehaunani New Member

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    Since I haven't driven the car yet today, I went out and followed your steps to test. Getting 11.2V with all on except radio (not currently working).
     
  7. WilDavis

    WilDavis Senior Member

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    11.2 sounds a bit on the low side! At least 12V under load (head-lights and accessories), and ~13.8V (in "Ready" mode) if the TractionBattery and the Inverter are OK…
     
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  8. exstudent

    exstudent Senior Member

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    Found a useful SOC (State Of Charge) chart. IMG_1510.JPG
    Remember, ambient air temp has a big impact on SOC readings. Cold Winters will have lower number readings than warm/hot Summers. Best to check batt like you have been doing: first thing in AM, which is plenty of time for any recent chargng from inverter to dissipate. Checking too soon after a recent drive will give a false high.

    11.2V is LOW. Factory radio would not present much of a load; maybe 11.0-11.1 reading, if radio was part of load test.

    Get battery recharged or replace.

    Useful to have a charger at home.
    Scumacher SSC-1500A/CA, $54.80 at Amazon.

    CTEK MUS 4.3, $63.75,

    Noco Genius G3500, $59.95,
     
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  9. Kehaunani

    Kehaunani New Member

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    Aha! I will order that 12V battery today. Even if it isn't causing the warning light, I had better not be caught with a dead batt away from home (car theft is a major major concern in my district). Will also get thee to dealer next month to see if there are any stored codes. In the meantime hoping for the best. Thank you for your valuable advice. Love priuschat.
     
  10. 05PreeUs

    05PreeUs Senior Member

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    In HawaiI, with the bright sun and moderately high temps, the 12v would not be expected to last more than 5-7 years MAX.

    Was the HV battery new from Toyota? If not, don't discount it as a possible cause as rebuilt batteries are often as good a bet as the tables in Vegas.

    FIY, you can jump a Prius from most motorcycles, the 12v in these cars is only slightly greater in capacity than many modern bikes.
     
  11. Kehaunani

    Kehaunani New Member

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    Yep, new HV battery from Toyota dealer here. They were only choice; I had to leave car at dealer for 3 weeks while they shipped the HV batt in. No loaners and crappy bus service. Nightmare. But still love my prius!
     
  12. 05PreeUs

    05PreeUs Senior Member

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    Yup, when customers have no options, dealerships quickly become STEALerships.
     
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  13. exstudent

    exstudent Senior Member

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    Why not buy miniVCI ($20-30) from Amazon? Install onto an obsolete 32bit Windows laptop (XP, 7), as a precaution against any malware the hacked Techstream software might have. You will now have dealer leve diagnosis capabilities!

    One code reading trip to the dealer is usu a minimum of $100+.

    Only do this if you can live with the guilt of using pirated software. If only Toyota would price the software reasonably or do what Microsoft and Adobe do, cheap subscription pricing.
     
  14. Kehaunani

    Kehaunani New Member

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    Reading up on the miniVCI and very interested, esp since dear Prius is 11 yrs old. Now looking around for an old/refurb laptop. Saw some on ebay. Thanks for pointing this out. When I had seen others mention the MVCI I took a quick look and thought it was another version of an OBD scanner. Didn't know about the Techstream aspect.
     
  15. exstudent

    exstudent Senior Member

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    Ask co-workers/friends/family if they know anyone in IT (Information Technology). These people will likely have access to obsolete 32bit Window laptops just sitting around, or they will know someone who will likely have a spare collecting dust.

    All the mini VCI cables on Amazon, crapBay (eBay), will likely come from the same one or two suppliers in China. It really doesn't matter who you buy from. B/C these are knock off cables, there is no quality control; some cables will work, some will work intermittently due to a bad pin. Ultimately, luck of the draw.

    Techstream software is the only way to go, if you want to read ALL of the codes on the Prius. Everything else is junk b/c those universal OBD2 readers CAN NOT read ALL of the Prius ECUs, or misread, and are unable to bleed the Prius brakes. The latest software version will be required for the latest (newest 2018 model year) Toyota. Toyota = Toyota, Lexus, Scion, Daihatsu (JDM); anything made by Toyota, you can read.
     
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  16. uart

    uart Senior Member

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    It doesn't really sound like an inverter coolant pump problem to me. That usually shows up under sustained hard driving in hot weather. You'd be the first person that I know to report it only showing after returning to the car while it had been sitting for 15 min.

    I don't think it's related to your 12V battery either.

    TBH it sounds more like the traction battery overheating.

    - Did the dealers check and clean the battery cooling fan when they did the battery?
    - Do you ever hear the fan in the back running at moderate to high speed?
    - Is there a lot of downhills on your trip from work to town, and when this has happened have you been parked with a high state of charge (green bars showing on the energy monitor)?
     
    #16 uart, Oct 15, 2017
    Last edited: Oct 15, 2017
  17. uart

    uart Senior Member

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    BTW. A very easy way to check if the inverter is overheating is just to take a look at the 12V battery voltage in ready mode when this issue happens (while it's still hot).

    - If the inverter is not overheated then the 12V battery voltage will be about 13.8 volts or more.
    - If the inverter is overheated the 12V battery voltage will be about12.5V or less (as it won't charge the battery while overheated).

    This is a simple and definitive test.
     
  18. Kehaunani

    Kehaunani New Member

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    uart: Invoice for the traction battery only lists the part number and summary of costs, no details on what was actually performed. Will need to check with them. I don't hear the rear fan running. BUT the trip to town is entirely downhill for about 20 miles, then a few more miles of highway driving then a few stoplights. I will pay better attention to the bars when I park in the future. I do know that a majority of the descent is spent completely charged, full bars. Wish I could remember what the warranty on the new battery is. Been over a year but less than 2 since install.

    Will test the inverter next time the warning light comes on. Thanks for those instructions!

    Also will be taking a 2 hr+ drive in a few days that doesn't involve descending downhill 4000' on full bars. Will see if the warning light appears.

    ETA: watching some youtube videos now to see how to get to the cooling fan so I can make sure its clean.
     
    #18 Kehaunani, Oct 15, 2017
    Last edited: Oct 15, 2017
  19. uart

    uart Senior Member

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    Yeah, it's sounding more and more like the battery overheating. The battery can heat up when it gets right up to maximum charge levels like that.

    When you park the car the battery fan turns off, but the heat is still building up in the pack, so it happens exactly like you said. When you return to the car 15 to 30 minutes later the battery can be overheated. This exact same thing happened to me a few years ago, and when I checked it out, the cooling fan was all clogged up with dust.

    One thing seems odd though. In my case, when I returned to the Prius after about 15 minutes the first thing I noticed upon turning it on was that the rear cooling fan came on quite loud (and I know it wasn't loud like that when I had turned it off 15 minutes earlier, so the heat definitely had built up while it was off).

    I'm not sure why you're not hearing the fan, but you should make sure that it is indeed working properly. Start by just listening for it after any drive of 20 minutes or more on any moderately warm day. It shouldn't be loud enough to hear from the drivers seat, but if you leave it in ready and just walk around to the right rear door and put your ear to the vent you will definitely hear it humming away. (and feel some air flow). At least make sure that is working.

    You should also take a look at the fan and see if it's clogged. Here is a good thread to read on this, and I've linked to some photos I took while cleaning mine which shows the location of the blower. See how much gunk was in mine. Fur and dirt causing major battery problems | Page 2 | PriusChat
     
    #19 uart, Oct 15, 2017
    Last edited: Oct 15, 2017
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  20. Kehaunani

    Kehaunani New Member

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    So, my battery fan was shockingly not that bad, considering my dog sits right in front of the intake on a daily basis. Attached is photo. They must have cleaned it when replacing the traction battery (unlikely) -or- its not working. I will drive around tomorrow, warm up the car, and listen for that fan.

    BUT I discovered my 12v battery was sitting in about 2-3 inches of clear, odorless liquid!!!! What is that?! I searched this forum but no one else has had this issue? I live in a rainforest - tons and tons of rain. I don't see any evidence of leaking from the top of the hatch area. Surely the battery acid isn't clear and odorless? I have attached a couple of pictures, best I could get in a tight space, but you can see the waterline. And I don't see any corrosion. Huh?.

    EDIT: I was just panicked and not using the correct search words. Tons of posts about water in the battery compartment. I'm off to read...
     

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    #20 Kehaunani, Oct 16, 2017
    Last edited: Oct 16, 2017
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