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Cruise Control - Intermittent Problem

Discussion in 'Gen 2 Prius Main Forum' started by Tomel51, Dec 12, 2011.

  1. Tomel51

    Tomel51 Junior Member

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    My Prius is a 2009 with 30,000 miles.

    Have just begun to have an intermittent problem with the cruise control (has happened twice in past month -- never happened before).

    Turn cruise control on, but it will not set. Turning off cruise control and turning it back on didn't solve the problem. However, stopping and turning the vehicle completely off and turning it back on did solve the problem. The second time this occurred (this morning), the engine sounded like it was revving and seemed somewhat sluggish (not what you'd expect if the engine was revving). Not revving real fast, but noticeable.

    Any thoughts? Don't want to waste time at the Dealer only to have them tell me they can't replicate the problem. However, would like to address the problem before my 3 year warranty expires in February.
     
    #1 Tomel51, Dec 12, 2011
  2. jdenenberg

    jdenenberg EE Professor

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    1. Cruise control is disabled in "B" which caught me once or twice in 8 years.
    2. If a code is set due to an HV battery problem, both the cruise control and AC will be disabled to allow your Prius to continue to function with a weakened HV battery. You would also hear more ICE reving than usual and the battery SOE would fluctuate more quickly than normal. This was the first symptom I noticed as my HV battery was dying at 200k miles. A couple of weeks later my 2004 Prius threw a P0A80 code (Bad battery module).
    The battery has a 8 year/100k mile warranty which is extended to 10 years/150k miles in California emission rules states. So don't sweat the expiration of the 36 month/36k mile warranty. (The power train warranty is 5 years/60k miles)



    JeffD
     
    #2 jdenenberg, Dec 12, 2011
    1 person likes this.
  3. qbee42

    qbee42 My other car is a boat

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    Most likely the OP was driving in B mode. Both symptoms suggest that.

    Tom
     
    #3 qbee42, Dec 12, 2011
  4. Tomel51

    Tomel51 Junior Member

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    Thanks for the feedback. I definitely did not have it in B mode. I have never used B mode and put in in D simply by reflex without even looking. However, just to make sure, I tried it in B mode this morning and it definitely was not the same feeling. B Mode is a downshift which increases revs and power. When my problem occurred, it sounded like the revs increased, but the power actually dropped -- the power felt sluggish like you'd expect when doing an upshift with a manual transmission at too low of a speed.
     
    #4 Tomel51, Dec 14, 2011
  5. sidecar

    sidecar Member

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    anything else changed recently, like MPG ?
     
    #5 sidecar, Dec 14, 2011
  6. seilerts

    seilerts Battery Curmudgeon

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    That has the look and feel of a communication error. The combination meter passes speed info to other ECUs. It might be going bad. It is a virtual guarantee that the dealership will not be able to help you unless you can reproduce it.
     
    #6 seilerts, Dec 14, 2011
  7. qbee42

    qbee42 My other car is a boat

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    B mode is *not* a down-shift, and certainly doesn't produce more power. When not braking (both explicit and simulated engine drag), B mode feels identical to D. During braking, B mode will increase engine RPMs to dissipate regenerated energy.

    Tom
     
    #7 qbee42, Dec 15, 2011
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