Please HELP: Acceleration issues, VSC, Check Engine, Red Triangle

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by PairofJacks, Apr 29, 2017.

  1. PairofJacks

    PairofJacks New Member

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    2006 Prius with 183,000 miles. NEVER had an issue until two weeks ago. Replaced hybrid battery less than a year ago. Two weeks ago I took it in for an oil change and two days later the red triangle, VSC, check engine, and circle with exclamation mark came on. I read forums and thought it must be the 12v battery. Replaced it and the lights came back on a day later. Took it to a Toyota dealer and they said the 12v battery wasn't good and that's what the codes showed. Also said the battery fan was clogged so they cleaned out the fan and today I returned and replaced the 12v battery. After getting the oil change and the lights coming on I started noticing an acceleration issue when I'd step on the gas. This hesitation was never there before. Today, while on the highway, I was in dead stop traffic and when the traffic opened up I accelerated and the car wouldn't go. I had the pedal all the way to the floor and it was slowly, very slowly, accelerating. Even lightly trying to accelerate it wouldn't go. I pulled off to the side of the highway, shut the car off and started it up and it accelerated fine the rest of the way home.

    What could be causing the acceleration issue? Bad oil? Exhaust issue? Throttle sensor?
     
  2. dolj

    dolj Senior Member

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    A bad or failing HV battery. What was the replacement you put in less than a year ago? Toyota new?
     
  3. PairofJacks

    PairofJacks New Member

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    Dorman. Has a warranty but shouldn't I have received a code saying there were issues with the HV battery?
     
  4. dolj

    dolj Senior Member

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    These lights mean you have codes. If you do not see the codes the reader you are using is not up to the job.
     
  5. PairofJacks

    PairofJacks New Member

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    The Toyota dealer said the only code that showed anything was wrong was with the 12v battery and suggested I replace it, which I did but the car is running the same way....acceleration issues.
     
  6. dolj

    dolj Senior Member

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    If the problem is a poor connection at the 12 V battery, it is conceivable that the codes are erased when the car looses connection with the 12 V. Check that the connections are tight at the 12 V.

    If that's not it, there is something awry. There should be other codes besides the one that the dealer found. What was it btw?
     
  7. biglew8

    biglew8 Active Member

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    Try to find the codes from your invoice and post them here. If you can't find your invoice, go on Toyota owner's website site and see your vehicle service history. It should be there.
     
  8. TwoTooMany

    TwoTooMany New Member

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    Hi @PairofJacks / OP,

    I've had almost the exact same problem. We recently replaced the HV battery, dealer pulled codes and cleaned fan, then replaced fan, then we replaced the coolant flow control valve, but still having a flash of red triangle, only on acceleration.

    What did the problem end up being? What fixed it?
     
  9. dolj

    dolj Senior Member

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    Have you checked your oil level lately?
     
    Raytheeagle likes this.
  10. DesiGuay

    DesiGuay New Member

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    Did you ever get this figured out? I’m having the exact same problem with my 2006 Prius, the day after getting an oil change.
     
  11. RichE

    RichE New Member

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    I took my Dad to the airport in his 2009 Prius. While driving it back to my home, I noticed it did not shift. The engine just continues to rev higher as I accelerate. Is this normal for this car? Is there only one gear? It seemed to be running at a high RPM but I could not find a tachometer. Thank you!
     
  12. dolj

    dolj Senior Member

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    How many miles are on the car?
    Technically, yes there is only one gear. The car has an electronically controlled continuously variable transmission, so it is one gear set, but, under computer control, it can set any gear ratio as required to match the power requirement requested by the go pedal. This is coined eCVT by Toyota and it is quite a different set up to the older conventional belts and pulleys type of CVT.
    Yes, it is and at the same time no, it isn't. if there are warning lights on the dash, It sounds like something could have gone wrong in the hybrid system, maybe a fault has developed in the hybrid vehicle (HV) battery (this is the big 201 V DC battery behind the rear seat), as it should sound more like a normal automatic car.

    Are there any lights on the dash (you don't say)? I am assuming there are, as you have tacked onto a thread that has lights on in the title. If there are lights on the dash, they indicate that there are diagnostic trouble codes (DTCs) to be read by a scanning tool. These could be set by one or more of the 11 - 14 electronic control units (ECUs), so the code reader needs to be more capable than a budget reader that only read the Engine Control Module (ECM) (called the Engine Electronic Control Unit (ECU) by Toyota) and maybe the ABS ECU.

    Once you have the DTCs you will know what is wrong with your Dad's car. Again, once you have read the codes, you could try clearing them and see what codes come back and how quickly they do. What to do next depends on the DTCs you get.

    I hope that helps as a launching pad.
     
    #12 dolj, Feb 5, 2020
    Last edited: Feb 6, 2020
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