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Diagnostic help with Warning lights

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Timmoth, Jul 20, 2017.

  1. Timmoth

    Timmoth Junior Member

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    Hello all, new account but I have used posts here to help me since I bought my prius almost a year ago. Here is the information as it stands now after searching the forums here and trying a few things:

    Today my dashboard lit up: it started with the red triangle (which beeped and said "problem"), accompanied by "CHECK" (check engine), "VSC", AND "(!)" lights. After one stop and restart, the only lights which stay on are "CHECK" and the Red Triangle.

    I did the diagnostic on the 12V battery: it held ~12.2V after startup, and when the headlights were turned on it held in the mid-upper 11V range.

    All caps (oil, gas, etc) were secure.

    MPG has been down about 10% for the last few days to a week.

    There is a not-too-loud noise (it's really not very loud) coming from the area between the Hybrid battery and the engine while on but not running. This could be a noise that happens all the time, I do not know. Just trying to give all information. It does not sound horrible or anything. The inverter coolant level seems to be right on or below the "LOW" line, which is a reservoir which is near that noise. Again, not sure if the noise is unusual, just giving info.

    If I think of anything else, or discover any new issues, I'll update. I plan on taking the car in tomorrow morning if no other solution develops in the mean time.

    Thank you in advance! This site seems to be full of great and helpful people. Cheers!
     
  2. bisco

    bisco cookie crumbler

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    welcome!

    i think you need a new 12v. and maybe more, but we'll need the codes. how many miles on her?
     
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  3. Timmoth

    Timmoth Junior Member

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    Thank you!

    149,600. Will Autozone be able to read Prius codes? I was reading where the dealerships charge
     
  4. JC91006

    JC91006 Senior Member

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    I think you have an inverter pump failure. But AutoZone can read the codes
     
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  5. Timmoth

    Timmoth Junior Member

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    And will the codes show if it is an inverter pump failure?
     
  6. JC91006

    JC91006 Senior Member

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    Yes p0a93
     
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  7. Timmoth

    Timmoth Junior Member

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    Excellent, thank you! I will update what the problem was when I get the codes
     
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  8. johnjohnchu

    johnjohnchu Active Member

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    I also think it is the inverter pump. I had the exact same issue just last week. If there is inverter pump issue, (1) there will be no liquid movement in the inverter coolant reservoir, (2) A/C will work only when the car is cold, (3) inverter may be real hot to the touch. (4) substantial decrease in MPG (up to about 20% in my case) (5) may have strange faint always-on new noise in the engine compartment
     
    #8 johnjohnchu, Jul 21, 2017
    Last edited: Jul 21, 2017
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  9. Timmoth

    Timmoth Junior Member

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    Now that you mention it, the A/C had not been working very well the last few days. Also I noticed that when I opened up the hood the kickstand bar was hotter than normal to the touch.

    This sounds like a pretty good candidate. If it does end up being the inverter, would it be best to take it to a dealer, or would a local place be better? As far as pricing or service quality goes. The nearest dealership is actually 15 or 20 miles away. Is it safe to drive that far?
     
    #9 Timmoth, Jul 21, 2017
    Last edited: Jul 21, 2017
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If the inverter pump has failed, go to a local Toyota dealer for service. A "local place" which is unfamiliar with Toyota hybrids may not even be able to find the pump (located behind the driver's headlight assembly), let alone successfully replace it.
    If you wish to DIY:
    How to Replace the Inverter Coolant Pump | PriusChat
     
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  11. Timmoth

    Timmoth Junior Member

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    The nearest dealership is 18 miles from me. It is safe to make that trip?
     
  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If you go very early in the morning when the ambient air temp is 65 degrees, you might make it without a problem. I would not wait until the air temp is 90 degrees to start the trip.
     
  13. johnjohnchu

    johnjohnchu Active Member

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    I took my car to the dealer approximately 20 miles away real early in the morning around 7 AM.

    According to the dealer, the inverter pump should be considered as a consumable item and it should be replaced every 5 years or so.

    MPG went back up to normal after the repair.
     
    #13 johnjohnchu, Jul 21, 2017
    Last edited: Jul 21, 2017
  14. Timmoth

    Timmoth Junior Member

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    I just checked to flow in the inverter coolant reservoir and the flow seems to look good, though I have not checked that before to have something to compare. I went by a vid on youtube and it looked strong.
     
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If you see fluid turbulence in the inverter coolant reservoir, then the inverter coolant pump is OK. Can you measure voltage across the 12V battery when the Prius is READY? If you measure 13.8VDC or so, that will show the DC/DC converter in the inverter is working OK.

    You will need to have the fault codes read to get a clue about the root cause of your car's problems. Since the check engine light is on, the engine has some sort of problem. You've also said the AC is not working very well, which probably is a separate issue (such as low refrigerant due to a minor leak in the system, for example.)
     
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  16. Timmoth

    Timmoth Junior Member

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    I don't have a voltmeter to check, but I'm sure I can find someone who does. I am a mile from an autozone, so I will head there and get codes if possible.

    Another diagnosis I've seen on youtube and on this forum which has my same symptoms is a bad traction battery module. I guess I will see in the morning.
     
  17. Timmoth

    Timmoth Junior Member

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    Autozone only had a cheap diagnostic tool, and no codes came up on the test. I have to take it somewhere with a better tool.
     
  18. JC91006

    JC91006 Senior Member

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    Warning lights still on?
     
  19. Timmoth

    Timmoth Junior Member

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    Yes, warning lights are still on. Actually the CHECK, (!), VSC, and Red Triangle are all back on.
     
  20. JC91006

    JC91006 Senior Member

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    Well there would be codes then