Can extreme heat cause my Prius C to act odd?

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Cable387, Jun 29, 2013.

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  1. Cable387

    Cable387 New Member

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    So my girlfriend and I went up to Big Bear for a 3 day vacation. Car was fine up there, on our last day there we left a little early to spend the rest of the day in Disneyland. Car was driven for 100 during that stretch and we had a bit of an elevation change. Anyways, ever since that day our Prius C has been odd. It won't go into EV mode at stoplights, and when I let off the accelerator I hear a sound for about a second after that sounds like the engine dying down, or like it's having trouble shifting into another gear. This is leading to us getting horrible fuel efficiency. It will stay around 30mpg all the time now, and my girlfriend said she got 16mpg while heading to work today. It worked fine for me this morning and I got 52mpg while on my way to work, but that was in the morning when it was still rather cool out. When my girlfriend used it later in the afternoon, that is when it started acting weird again.

    It has also been extremely hot here though. We live in SoCal and it's been 100+ degrees these days. Is the extreme heat making the cars engine stay on so the fan will keep the engine temp down? The fluid levels are fine, so I was just wondering if anyone has experienced this, or if I need to make an appointment with my Toyota service center since we just bought this car in March this year.
     
    #1 Cable387, Jun 29, 2013
  2. bisco

    bisco cookie crumbler

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    the car has a battery protect mode to prevent overheating. i'm surprised you don't get any warnings. do you keep the a/c on max?
     
    #2 bisco, Jun 29, 2013
  3. Cable387

    Cable387 New Member

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    Dug through some old threads and I may have found a solution. Someone else had a similar problem. My HV Battery vent in the backseat was covered up by a grocery bag with some Gatorades in it. The verdict isn't in on whether that was the problem but I removed the blockage and will see how it does the next time I drive it.
     
    #3 Cable387, Jun 29, 2013
  4. Drdiesel

    Drdiesel Active Member

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    That will cause problems as the battery needs to be cooled. They say it prefers about 70°F
     
    #4 Drdiesel, Jun 30, 2013
  5. SquallLHeart

    SquallLHeart The Techie Guy

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    the engine likes it hot, the traction battery inside the car likes it cool.

    with me running AC and in eco mode, the car has performed with better mileage. California has gotten quite hot, but make sure the interior cabin of the car stays cool. sometimes it's better to run the AC than just having the windows down.

    have you been running the AC?
     
    #5 SquallLHeart, Jun 30, 2013
  6. bisco

    bisco cookie crumbler

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    keep that vent clear!(y)
     
    #6 bisco, Jun 30, 2013
  7. ztanos

    ztanos All-around Geek!

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    I was just about to mention that. Great usage of the search feature. :)
     
    #7 ztanos, Jun 30, 2013
  8. Cable387

    Cable387 New Member

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    Yeah, the engine stopped making that sound I was hearing but gas mileage is still suffering a bit. Not as bad as before. No more 16mpg trips, but dropped my girlfriend off at work today and had 29mpg there, and normally I'm pretty sure I get around 38-39mpg on that trip. So yeah, it has helped and I hope my mpg starts getting back to normal. Any chance having that vent blocked for a couple of hours could have caused any further damage?

    So like I mentioned, no more extra engine noise, but I feel like my acceleration is off now. I feel like I'm barely on the pedal sometimes, and my acceleration shoots up to the "Power" range on the dashboard screen. Still need to drive it a bit more but something still feels off.
     
    #8 Cable387, Jun 30, 2013
  9. bisco

    bisco cookie crumbler

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    hopefully, nothing was damaged, but the heat might have damaged a cell. again, i would think you'd get a warning on the dash.
     
    #9 bisco, Jun 30, 2013
  10. Ashley7

    Ashley7 Active Member

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    Running the AC, especially on full blast, can have this effect. I can typically make a long left turn from a stoplight without leaving EV, but with AC on, it immediately jumps up and starts the ICE. AC uses a lot of power.
     
    #10 Ashley7, Jul 1, 2013
  11. Drdiesel

    Drdiesel Active Member

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    Run your A/C with the Eco button on. It makes it more efficient and uses less power. Works good for me.
     
    #11 Drdiesel, Jul 1, 2013
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  12. Cable387

    Cable387 New Member

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    Yeah, I'm blaming it on the heat. Car performed amazingly when I picked my girlfriend up from work. When I get into the car midday, the internal temperature of the car is easily 105+ degrees right now so it has nothing but hot air to circulate to the HV battery and my mpg suffers because of it. When I get into the car early morning or at night, the air inside the car is pretty cool or merely warm so car performs as I've expected it to. These SoCal Summers man...
     
    #12 Cable387, Jul 1, 2013
  13. Drdiesel

    Drdiesel Active Member

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    Roll down all the windows to evacuate the heat and turn on the A/C with the Eco button on. After the inside
    cools down with the windows open, close them and enjoy the A/C and high MPG's. I noticed a 2 MPG loss
    over a tank while using my A/C. Not bad. Try that with any other car and see what happens :ROFLMAO:
     
    #13 Drdiesel, Jul 2, 2013
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  14. firstrival

    firstrival Member

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    I also lost about 5-7mpg during the past 10 days in NorCal with 100ºF+ heat.
     
    #14 firstrival, Jul 7, 2013
  15. Drdiesel

    Drdiesel Active Member

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    Did you use the A/C with the Eco mode activated ? Did you set your auto temp to 65° or higher ?
     
    #15 Drdiesel, Jul 7, 2013
  16. MoarMPGplz

    MoarMPGplz Junior Member

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    Not sure if my Prius-c experienced similar HV battery issues, but it had been extremely hot out here the past week with ambient temps exceeding 108-117f during the hottest time of the day. My car sits outside while I'm at work, so I always put up the sunshades for the windshield to minimize the heat build-up inside the car. When I left from work a few days ago, I noticed the HV battery was discharging and not charging up like it normally does after the ICE comes on. I drove it for about a couple miles and the HV battery drained down to 2 bars and stayed there. The A/C was on as well to help cool down the interior and noticed the ICE was constantly running even while I was stopped. The EV light did not come on. I ended up stopping at a fast-food place to get a bite to eat, then drove back home. As I drove off, I noted the HV battery still showed 2 bars and the ICE stayed on as before even while stopped. I noticed there was a lack of power as I accelerated onto the freeway onramp with the ICE spinning at a much higher RPM than normal, likely because the HV battery was not assisting the ICE. However, as I drove on the freeway for a few miles, the HV battery slowly started charging back up. By the time I got home, the battery was at its normal SoC...a couple bars from full. There was also a significant drop in MPG's...normally I get around 55-60 MPG on most trips, but this time it was showing around 40 MPG. Throughout this whole experience, there were no warning lights on the display to indicate something was wrong, so I can only guess that the HV battery temp was too hot to work properly. The past couple days have not been nearly as hot and the car has been behaving normally with average MPG's back to normal. I have seen this particular behavior happen only one other time since I've been driving the 'c'. The last time was also when it was really hot, in August last year.
     
    #16 MoarMPGplz, Jul 7, 2013
  17. Drdiesel

    Drdiesel Active Member

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    Yep! The battery was hot and the freeway airflow pulled the heat out. Always make sure your vent isn't blocked by
    items laying over it. While you're driving next time, reach back and feel the vent. You'll learn quickly what speeds create airflow through the system.
     
    #17 Drdiesel, Jul 7, 2013
  18. Rob.au

    Rob.au Active Member

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    Seriously, you can do that? :eek:

    Down here I am of course positioned on the other side of the car, but I cannot imagine being able to do that even if I was driving from the left seat.
     
    #18 Rob.au, Jul 20, 2013
  19. Drdiesel

    Drdiesel Active Member

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    I drive with my seat all the way back. It's easy to reach behind my seat and feel the vent grill :D
     
    #19 Drdiesel, Jul 20, 2013
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  20. Deleted member 111882

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    Yup... :LOL:
    We had 95 degrees with like 90% humidity recently, and silly me I had put the seats down and draped blankets over them to protect the seat back from a bunch of boxes. Yup, the blankets draped right over the battery vent. Fuel economy for me went down by like 5% compared to what I was expecting.
     
    #20 Deleted member 111882, Jul 22, 2013
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