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P0301 code with check engine light on

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Abu Rais, Nov 7, 2017.

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  1. danlatu

    danlatu Senior Member

    Joined:
    Apr 27, 2017
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    Location:
    maryland
    Vehicle:
    2011 Prius
    Model:
    Two
    Good eye. I just grabbed a pic from the internet, clear and big enough to reference the coolant reservoir. Probably euro/japanese right hand drive prius.
     
    #21 danlatu, Nov 8, 2017
  2. Abu Rais

    Abu Rais Member

    Joined:
    Mar 4, 2016
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    Location:
    Houston, Texas
    Vehicle:
    2010 Prius
    Model:
    Four
    Here is the spark plugs after 197 K miles.
    Installed new shocks and struts.
    EGV cooler left with Oxy clean and purple cleane.
    It was very dirty Inside.
    Intake manifold gasket changed and cleaned. Lots of oil found inside and cleaned them all.
    Tomorrow will complete installing the OCC. and put everything back together.
    This morning before I took the car for to do all that, I had a hard time to start the car. Car wouldn't start with a check Hybrid System light on and wouldn't shift to D.
    Took out 12volt battery and tested at autozone. Battery tested 100% working. Came back home and installed the battery and tried to start the car and on a 2nd try it started. No more message on the dash. Drove 5 miles and stopped for Gas and same thing car wouldn't start. Luckily I had wrench so I unplugged positive treminal from the battery and put it back and car started. I drove then to the shop and stopped the car and Same problem.
    I called Hometown Hybrids and explained them the situations and the recommend to take the car at Dealership and check for Diagnostic code. Without any code they can't help.
    Plan is now to put back everything tomorrow and then drop the car at the dealership for full diagnosis.

    Any suggestions guys?
    I am doing my best to keep the car but rest is on God. Hoping for the best but this no stat is big headache. I think it's something electrical issue.
     

    Attached Files:

    #22 Abu Rais, Nov 9, 2017
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  3. mjoo

    mjoo Senior Member

    Joined:
    Nov 9, 2016
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    Location:
    Michigan
    Vehicle:
    2010 Prius
    Model:
    III

    The engine should run much better after cleaning your intake manifold and EGR cooler. Just give us a report after you're done.

    It takes around 3 hours to remove & reinstall the wiper cowl to get to the spark plugs. So while you're in there you might as well change the plugs. Also clean the PCV, MAP sensor and MAF sensor with MAF sensor cleaner.
     
    #23 mjoo, Nov 9, 2017
    Last edited: Nov 9, 2017
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  4. Abu Rais

    Abu Rais Member

    Joined:
    Mar 4, 2016
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    Location:
    Houston, Texas
    Vehicle:
    2010 Prius
    Model:
    Four
    Which one is MAP sensor and MAF sensor. I already installed a new PCV.
     
    #24 Abu Rais, Nov 9, 2017
  5. mjoo

    mjoo Senior Member

    Joined:
    Nov 9, 2016
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    Location:
    Michigan
    Vehicle:
    2010 Prius
    Model:
    III
    MAP is by throttle body. MAF is by the air filter

    Pixel XL ?
     
    #25 mjoo, Nov 9, 2017
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  6. Abu Rais

    Abu Rais Member

    Joined:
    Mar 4, 2016
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    Location:
    Houston, Texas
    Vehicle:
    2010 Prius
    Model:
    Four
    Found the MAF picture.
    Can you share one picture for MAP so I can find that to clean.
     
    #26 Abu Rais, Nov 9, 2017
  7. Michael48

    Michael48 Junior Member

    Joined:
    Dec 13, 2016
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    Location:
    Seattle
    Vehicle:
    2012 Prius
    Model:
    Two
    Did you figure this out?
     
    #27 Michael48, Mar 28, 2018
  8. specul8tor

    specul8tor Junior Member

    Joined:
    Oct 19, 2009
    5
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    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    II
    My generation 3 Prius had a terrible engine rattle when I started it one day. It caused the check engine light to go on, and I drove it to AutoZone to get it diagnosed. The code was PO301 but and the person at AutoZone said it might just be a bad spark plug. I have 106 k miles on my 2010 Prius and have never changed the plugs. So I bought a set of four thinking I would change them all at the same time. After reading a little more about the rattling problem, I concluded it might have been due to starting the engine up and not letting it warm up, it had happened the day before when I moved the car out of the garage onto the driveway and back. I then thought the rattling and misfiring was due to that, so I erased the error code. It drives fine and has no issue. So before you do anything, I suggest erasing the code and seeing if it returns, it might be a real simple thing that set it off.
     
    #28 specul8tor, Dec 27, 2018
  9. JC91006

    JC91006 Senior Member

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    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    I would treat the p0301 as a warning that something bad is in the near future. It's a misfire code. Erasing the code is like taking a 12 hour pain medication, which gives you short term relief.

    At 106k miles you are coming up on needed maintenance.
     
    #29 JC91006, Dec 27, 2018
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