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Gen 2 2007 revs up on releasing gas pedal

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Jakov Glavina, Sep 9, 2020.

  1. Jakov Glavina

    Jakov Glavina Junior Member

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    Hi all,

    I have an unusual issue with my 2007 Gen 2 Prius, it has been regularly mantained, 150k km (93k miles) and without any issues until recently.

    Yesterday I noticed, that when I let go of the gas pedal, I can hear the car engine working more loudly instead of it either working with less intensity or completely turning off. So, lets say I'm driving at 80 km/h (50 mph) and when I let go of the gas pedal, the engine starts to be more loud and it revs up, as if you were driving in 3rd gear downhill on a regular manual transmission car. I tried reproducing this issue multiple times with success. So the car works on higher RPM instead of a lower one. This happened regardless of the speed at which I was driving. Everytime this happened, if I stopped and turned off the car, and then turned it on again, the issue would go away.

    Has anyone else experienced a similar issue? Do you know what might be the culprit?
     
  2. bisco

    bisco cookie crumbler

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    check the battery health
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Try cleaning throttle body.
     
    Aaron Vitolins and jerrymildred like this.
  4. donbright

    donbright Active Member

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    is your cruise control indicator light on in the dash?
     
  5. dolj

    dolj Senior Member

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    Are you using the gear selector in "B" or "D"?

    What colour are the bars on the battery graphic on the Energy Monitor screen?

    Are the arrows displayed showing energy going into (or out of) the HV battery?

    Any warning lights on the dash? If so, have you checked for codes?

    Do the brakes feel like they are working normally?
     
  6. Jakov Glavina

    Jakov Glavina Junior Member

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    The gear selector was in "D", not "B". The engine was running when I let go of the gas pedal but the current fuel consumption reading was 0 liters. Cruise control wasn't turned on. No warning lights were showed on the dash. As for the car battery, this is the first one, it was dissassembled and thoroughly cleaned 2 years ago, and new copper plates were fitted. The battery was in excellent condition (looked like new, and in general the battery health readings were fine). The battery cooling system was also cleaned. I don't think the battery degraded in any significant way, because that would reflect in the fuel consumption - the fuel consumption was normal, as well as the general performance of the car, and the battery was charging just fine. 95% of the time the battery charge is at optimal level (blue bars), very rarely at high levels (when driving downhill), and purple bars almost never. When this issue occured, the car's computer showed green bars (one bar above the blue bars boundary). This did occur when driving downhill (however the incline was not steep). I was driving on much steeper roads where battery charge levels would be well in the green bars range and this wouldnt occur. When I pulled over, turned off the car, turned it on again, the issue disappeared. I have now made 200 km since this issue went away, and it hasn't reappeared since.
    I'm not entirely sure as to what might be the culprit here...
     
  7. dolj

    dolj Senior Member

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    Having answered those questions, I have no further ideas.

    Maybe a really wild guess would be the battery management system was doing some kind of calibration or reset????

    On the face of it, I would think that it would not be something to be concerned about unless it happens again and with more frequency.
    Just one comment on this, this shows the engine was spinning but not running (consuming fuel), so it indicates the car was using engine braking in lieu of regenerative braking. Is that significant?