Trouble shooting EV mode button and EV light on dash

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Bmr4life, Jul 16, 2019.

  1. Bmr4life

    Bmr4life Member

    Joined:
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    Location:
    Atlanta, GA
    Vehicle:
    2014 Prius v wagon
    Model:
    V
    I have a 2014 Prius v with ~85,000 miles and I have two specific issues.

    1. The EV light goes out even when the car is still in EV mode. I've confirmed this using the energy screen in the radio (arrows show power to wheels is coming from the motor via the battey and the engine is off) and also via the instant mpg indicator (shows 99.9mpg)
    2. Very rarely can I press the EV drive mode button and the car actually lock into EV mode. This is from a standstill as well as going at low speeds with pressing the throttle pedal soft enough that I have no passed the EV mode bar on the dash. I know there several factors that control whether this can engage or not but my commute is long enough for then engine to get up to temp and for the battery to have a high SOC. This morning the EV mode button actually work near the beginning of my commute (with a pretty low SOC) but I could not get it to work again for the next 30 mins.
    I have confirmed that my battery is good, I can get about a mile of 100% EV mode driving with an almost full battery and still reach the max EV speed of ~45mph

    Also, this line from the manual is BS.

    *: Depending on the circumstances, EV drive mode may also not be switched to in situations other than those above.

    That's not very helpful.
     
    #1 Bmr4life, Jul 16, 2019
    Last edited: Jul 16, 2019
  2. cnc97

    cnc97 Senior Member

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    Location:
    Evansville, IN
    Vehicle:
    2010 Prius
    Model:
    Three

    Now I will tell you that I have a 2010 Prius, so none of what I say may apply, but things I have noticed.

    The EV light only comes on when I have pushed the EV button. I have to be at a standstill to get the EV light when pushing the button. Gear position is not relevant either. Park, drive, or even reverse.

    Lack of EV light does not necessarily mean I am not in EV mode. At the same time, if I have low HV charge, accelerate too fast, or exceed the max EV speed, I get the corresponding messages and EV light goes away.

    As long as you don’t have any error codes or warning lights, don’t attempt to outsmart the hybrid computer. It’s logic is not perfect, but it is programmed to do what’s best for the car 98% of the time I’d say.
     
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  3. Bmr4life

    Bmr4life Member

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    Location:
    Atlanta, GA
    Vehicle:
    2014 Prius v wagon
    Model:
    V
    This problem has continued and is random. I just went from having two 40+ mpg tanks to a 26mpg tank. This is all manually tracked.
     
  4. Raytheeagle

    Raytheeagle Senior Member

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    Bay Area, CA
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    And the driving for each of these tanks is the same as the prior tanks? Any differences in:
    • Traffic
    • Speed
    • Driver (you vs. a significant other)
    • Tire pressure
    • Terrain
    • Where you bought gas
    • Was each tank to the almost same level for filling up
    • Other factors
    A bit of background may assist us in helping with the next steps of troubleshooting ;).

    Good luck and keep us posted (y).
     
  5. Bmr4life

    Bmr4life Member

    Joined:
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    Location:
    Atlanta, GA
    Vehicle:
    2014 Prius v wagon
    Model:
    V
    I drove slightly less mpg mindfull after getting two consistent tanks in the 40s. Commute is extremely similar. I'm the only driver. Always fill up to the same first click which is between 9.8 and 10.5 gallons since I drive to E.

    Never has it dropped so low into the 20s, even when I was flooring it constantly through the Tennessee mountains for two hours straight I was still in around 29mpgs.

    I log every full up manually.

    Stormtrooper (Toyota Prius V) | Fuelly

    There is definitely something going on. The current tank started out very poorly and over the last 20 miles or so has completely flipped to being great on gas. First 65 miles were mid 20s and then it started creeping up to the high 20s for the average. I then switched over to trip B and reset it. Drove mildly aggressive for 20 miles and it's been in the 40s. Trip A average is now around 32mg and creeping up.

    I'm wondering if heat is a factor since I park my car outside for work but indoors on the weekends and when I work from home. I'm in the Atlanta area and last week was in the 90s and the last couple days were far cooler.

    I don't have any idiot lights warning me about motor or battery temp, but maybe I need to check on the battery fan.
     
    #5 Bmr4life, Aug 26, 2019
    Last edited: Aug 26, 2019
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  6. Raytheeagle

    Raytheeagle Senior Member

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    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Heat is always a factor;).

    I’d check tire pressures too and make sure they are where you left them. I run 38 up front and 35 in the rear:).

    Good luck and keep us posted (y).
     
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