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2010 Prius Hybrid Warning Light

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Helen Zeppenfeld, Aug 31, 2015.

  1. Helen Zeppenfeld

    Helen Zeppenfeld New Member

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    While driving the Prius the Check Engine Light -- Hybrid System Warning came on while driving in light traffic. Almost immediately, I lost power and limped the car home about 1 mile and parked it. I did try shutting the car off and restarting to no avail. The gas pedal was pushed to the floor and I barely got 10 mph of power. Since it was late on a Saturday evening, I started reviewing various forums to determine the nature of the problem. First thing Monday morning I had the Prius towed to the dealership on a flatbed tow truck.

    The dealership here in Pittsburgh ignored what I explained when I the details of the issue and tried to convince me this was not a problem and that only found one code that indicated there may be an issue with the hybrid cooling system. They had not driven the car to duplicate the issue but wanted me to pick the Prius up and continue to drive it to see if the warning lights reappeared.

    I opted to leave the car at the dealership since I do not feel comfortable driving the car while not knowing if it will lose power quickly, thus causing a rear-end collision hazard.

    Any suggestions welcome.
     
  2. IMkenNY

    IMkenNY Im just being nosy

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    I wonder if they checked for proper circulation and proper fluid level of the hybrid cooling system?
     
  3. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    Yeah, that def sounds like an inverter coolant pump failure. If you can go to the dealer, turn the car on, remove the cap from the inverter coolant reservoir and look for flow/movement of the fluid. Report the results back on this thread.
     
  4. JimN

    JimN Let the games begin!

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    What's the code?

    Register at Toyota Owners Official Web Site to see if the car is subject to any recalls. I wouldn't trust those clowns to reflash an ECU but they may be OK swapping parts on Toyota's dime. Perhaps having one of the other Toyota dealers handle the situation would be a good idea.
     
  5. Helen Zeppenfeld

    Helen Zeppenfeld New Member

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    Toyota dealership said there were no active codes so they cannot do anything unless I bring it in when the code is active. Guess I will be carrying my video camera with me now so I can prove there was an issue. They said they drove it 38 miles without anything and just called it a fluke. All the service on the Prius has been at Toyota dealerships so may be looking for another Toyota dealer.
     
  6. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    This is very likely not a fluke and it is very likely a bad inverter coolant pump. When you get to the car, execute the steps I spoke of in my earlier post and post the results here. Do not leave the dealer before doing this. If there is no flow thru the inverter coolant reservoir with the car on, point that out to the service rep.

    If he doesn't help you post that here (preferably before you leave the dealer). The reason I'm being so adamant about this is that this could cause a shutdown again and it may happen at the worst possible time. Don't drive the car until you check this for your safety.
     
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  7. JimN

    JimN Let the games begin!

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    "While driving the Prius the Check Engine Light -- Hybrid System Warning came on while driving in light traffic."

    A code was logged when the idiot light lit. Idiot lights are not like the randomly blinking lights on a pinball machine.

    "The dealership here in Pittsburgh ignored what I explained when I the details of the issue and tried to convince me this was not a problem and that only found one code that indicated there may be an issue with the hybrid cooling system."

    So, what code did they find?

    Your dealer's employees are incredibly lazy, incredibly stupid, or incompetent (that's not incredible).

    This illustrates why it is a good idea for everyone to spend a bit of money for a scan tool.

    I agree with the other posters. When you duplicate the circumstances or the problem gets worse the symptoms will reappear. Next time you might be on a bridge, going up a mountain, or down a mountain.
     
  8. Helen Zeppenfeld

    Helen Zeppenfeld New Member

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    Well, the idiot light came on today, and again I limped the Prius in never turning the car off. I provided the advise I received from this chat. The code that showed up today was P0A93 (previously the codes were P0A93/P0A94 but showed inactive since the car had been stopped and started several times.) Luckily I took it in while the idiot lights were on.

    The tech called into a Tech at Toyota and he said that is was probably an air pocket in cooling system for invertor and to bleed system with vacuum type system. The local tech said he road tested and Prius operating as designed.

    I specifically ask if they had removed the cap and check for coolant flow. They told me it was OK. At least I could stay with the car this time and ask questions while the mechanics were still working; although I am not sure the work was successfully accomplished this time.

    What is very upsetting is that the charge was over $116 for them to put the car on the computer. I questioned why this was not covered under the warranty of the hybrid system and was told that Toyota does not have an active recall on this issue.

    Looking up earlier recalls, several forums suggested contacting Toyota with documentation of the issue since Toyota stated this may occur on models later than '09:
    Toyota Motor Sales, U.S.A. Inc
    Toyota Customer Experience, WC10
    19001 South Western Avenue, Torrance, CA 90509

    Any thoughts?
     
  9. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    My thoughts are, I would want to see the flow thru the inverter reservoir for myself. I don't believe this is an air pocket in any way, shape or form. Once again, I cannot stress this hard enough. This is very likely a bad inverter coolant pump. I am also confident that most Toyota technicians have no idea how to check this.
     
  10. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    Here's the problem with all this. If he vacuums the "air pocket" out, he will never test the inverter coolant pump. Go to the service advisor and tell him you want to personally see the flow in the inverter reservoir before you leave the dealer. Do not leave the dealer without doing this.
     
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  11. Helen Zeppenfeld

    Helen Zeppenfeld New Member

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    Thanks for the feedback. I know where I will be spending my Friday. I was not getting any results from this dealership.
     
  12. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    can you check for flow right now?
     
  13. Helen Zeppenfeld

    Helen Zeppenfeld New Member

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    Can you give me some details how to check the flow.
     
  14. Helen Zeppenfeld

    Helen Zeppenfeld New Member

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    Looked at reservoir and it was to the top of the line. With engine running it didn't bubble at all. Put my hand on the top hose and all I felt was the vibration of the engine. I rev'd the engine up and checked it again with no change. It was the same when the engine went into electric mode. Haven't been under the hood when its running so not sure how the engine should sound. Will upload the video I took in a few minutes.
     
  15. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    turn the car on, remove the cap from the inverter coolant reservoir and look for flow/movement of the fluid. Do a google search for the location of the inverter coolant reservoir since I'm unable to access a pic of it from this computer or check your owners manual.
     
  16. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    Yep, that is a tell tale sign that the pump is bad. You should see noticeable flow thru the reservoir no matter what mode the engine is in (on or off). As soon as the car goes to ready, fluid should be flowing. If it is not (which I'm sure its not), your inverter coolant pump is bad. I told you these Toyota techs don't know what they're doing.
     
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  17. Helen Zeppenfeld

    Helen Zeppenfeld New Member

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    Let's see if this video uploads correctly. file://LHASARESCUE/Users/Helen/Pictures/DSCN1978.AVI
     
  18. bisco

    bisco cookie crumbler

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  19. IMkenNY

    IMkenNY Im just being nosy

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    How many miles are on your prius? (I expect 150,000 + mile life expectancy on third gen inverter pumps)
    Have you had the inverter fluid changed recently? (increasing the possibility of trapped air)
    Inverter pump failures are rare in the gen III Prius
    Inverter failures however are not as rare and Toyota stepped up to the plate with the recall and extended inverter warranty.
    The stored P0a94 suggest a possible inverter problem.
     
  20. usnavystgc

    usnavystgc Die Hard DIYer and Ebike enthusiast.

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    The fact that there is no flow thru the reservoir means the pump is not working. The inverter is not showing any symptoms of being defective.