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Check engine light from hatch open?

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by PegP, Mar 28, 2024.

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  1. PegP

    PegP New Member

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    I moved some furniture with the hatch open and check engine light came on and mpg dropped precipitously. FIXD said was running lean. Reset...light off. Under normal conditions, everything returned to normal...normal 54 mpg etc.

    Same scenario a week later. Moved furniture with hatch open. same engine check light, same FIXD response. Reset. Again returned to normal. Decided to never move oversized furniture again.

    Today, left car running, opened hatch to put stuff in (took a few minutes)...check engine light on again. Strong gas odor OUTSIDE car on side of car with gas tank. (checked cap....tight) Closed hatch, light still on. Drove home, retested with FIXD. Same 'running lean.' no decrease in mpg or any other issue.

    Why would running with the hatch open or even just leaving it open with car running for a few minutes kick off a 'running lean' code?
     
    #1 PegP, Mar 28, 2024
  2. Doug McC

    Doug McC Senior Member

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    It shouldn’t. Do you typically “top off” your tank when you fill up (put in a little more gas after the pump nozzle shuts off)?
     
    #2 Doug McC, Mar 29, 2024
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  3. BiomedO1

    BiomedO1 Senior Member

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    You should probably get the codes read by a Toyota specific Techstream OBDII unit. That will get the exact issue that your ECU is warning you about. The issue will more than likely return, because nothing is being done to fix the actual issue. Most likely a busted hose in your emission system, next to your fuel tank (ergo, strong gas odor - next to your capped fuel tank).

    That's my guess; Good Luck..
     
    #3 BiomedO1, Mar 29, 2024
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  4. vvillovv

    vvillovv Senior Member

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    Is your Prius and import? Your profile says Alpha.
    Have you tried any other OBD2 adapters or apps besides FIXD
     
    #4 vvillovv, Mar 29, 2024
  5. PegP

    PegP New Member

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    All I know is that it's a 2017 Pruis bought used from Carvana. I'm a 70 year old woman just trying to not be taken advantage of by a dealer or repair shop recommending 'fixes' that aren't necessary. No, do not top up tank. No, have not used any other testing methods. Is the testing offered by auto parts dealers different from FIXD? Strong gas odor only exists when car is left running with hatch open idling for more than a few minutes. Very puzzling.
     
    #5 PegP, Mar 30, 2024
  6. FuelMiser

    FuelMiser Senior Member

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    Does Carvana offer any kind of service/warranty? I've never used them, but CarMax, for example, has a complete repair shop in their facility and will fix things that come up within a certain time limit of purchase.

    Check engine lights (CEL) relate to emissions, and emissions relate to exhaust gases (O2 sensors, catalytic converters) and fuel vapors. There is a fuel vapor capture system on the Prius. Even if you did not overfill/top off the gas, maybe the previous owner did and messed up the fuel vapor capture system.

    It's quite possible you got a "lemon" from Carvana. Where are you in the warranty coverage terms of your purchase? Is it a recent purchase, or out of any warranty coverage?

    Fuel vapor repairs are not for DIY, I'm afraid.
     
    #6 FuelMiser, Mar 31, 2024
  7. BiomedO1

    BiomedO1 Senior Member

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    If there's a strong gas odor, the car is definitely NOT running lean. If it's your typical exhaust gas odor, then you may be OK. Have a trusted mechanically inclined friend excourt you to the dealership or get their opinion. Buy or make them lunch or dinner for their trouble. Sometimes a second pair of eyes or head will see something that you've missed...

    Hope this helps...
     
    #7 BiomedO1, Mar 31, 2024
  8. PegP

    PegP New Member

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    Turns out the issue was the mechanic who changed my oil left the oil cap off! What a mess!
     
    #8 PegP, Apr 9, 2024
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  9. Doug McC

    Doug McC Senior Member

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    I bet you will be checking under the hood from now on after you get your oil changed. ;)
     
    #9 Doug McC, Apr 10, 2024
  10. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    I left the oil fill cap off once, on a previous car. Never do that again..

    One good trick is to put the cap right next to hood latch, so it’ll stop the hood closing if you forget.
     
    #10 Mendel Leisk, Apr 10, 2024
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