2005 Prius hesitates to shut off ICE engine

Discussion in 'Gen 2 Prius Main Forum' started by Prius Rising, Apr 15, 2019.

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  1. Prius Rising

    Prius Rising Junior Member

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    I have been driving the car the past few weeks and I noticed that sometimes when I stop at a light and the car does a hard stall. It's like it doesn't want to shut down the ICE engine when it should. I am not getting codes for that but it is throwing the catalytic efficiency not optimal code. I also heard the accelerator pedal sensors can cause this. Anyone else had this issue? (n)
     
  2. bisco

    bisco cookie crumbler

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    how many miles on her? what code reader are you using?
     
  3. 09Prius2

    09Prius2 Member

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    If you havent changed your spark plugs you need to. They would be 15 years old and contribute to your catalyst code. Also air filter.

    That could be why it sounds or feels rough. If you change the plugs, clear the code and it comes back, your cat is actually bad and likely unrelated directly to the hard shutdown.

    However its a 15 year old hybrid. They dont run as smooth once they're not new anymore.

    One cause I've noticed at a stop is sometimes the battery is too full, so the engine is running unnecessarily which has something to do with protecting the hybrid system from too much voltage. This would go on for a minute or so and stall hard afterwards, presumably as if the engine just wanted to keep going.
     
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  4. Prius Rising

    Prius Rising Junior Member

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    209,000 on the chassis and 180,000 on the replacement motor. I am using the Torque pro reader. The only codes it is throwing are bad 3 way valve (it's brand new) and the Catalyst non efficient in bank one. Also, there is a large difference in the Catalyst bank temps. It may be a clogged converter. What do you think?
     
  5. Prius Rising

    Prius Rising Junior Member

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    Plugs are brand new as well as the air filter,
     
  6. bisco

    bisco cookie crumbler

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    i'm not sure that torque picks up all the correct codes. i think @ericbecky knows
     
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  7. Prius Rising

    Prius Rising Junior Member

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    Ya, It is throwing the p1121 code that Torque pro says is a "pedal position sensor" issue but the whole internet says it a bad 3 way valve code for Prius. I heard about the 3 way valve issues and inverter pump issues and changes them both with new when we changed the ICE engine. I have read that the throttle position sensor (throttle pedal) goes bad in the gen 2 and the symptoms would align with that but I don't want to just start throwing parts at it without having more info.
     
  8. ericbecky

    ericbecky Hybrid Battery Hero

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    The code is correct, just the description is wrong.
    I never trust Torque descriptions.
     
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