2015 Prius V 3 Trouble Codes

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by AZaly, Nov 9, 2025 at 10:17 PM.

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  1. AZaly

    AZaly New Member

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    Could these codes indicate the ignition coils and spark plugs need to be changed or is there additional repairs needed.

    See photo attached.
     

    Attached Files:

    #1 AZaly, Nov 9, 2025 at 10:17 PM
  2. Brian1954

    Brian1954 Senior Member

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    Those are historical codes. They are not current or active codes. There is nothing to worry about unless they are current codes.

    How many miles on the car?
     
    #2 Brian1954, Nov 10, 2025 at 5:53 PM
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  3. BiomedO1

    BiomedO1 Senior Member

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    Yep; It could've happen with a loose gas cap on the emission control code.

    The cylinder #2 misfire may indicate something - check your engine coolant level (passenger side reservoir).
     
    #3 BiomedO1, Nov 10, 2025 at 6:01 PM
  4. AZaly

    AZaly New Member

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    I cleared the codes the 1st time and the 2nd time I scanned it, they reappeared.

    When the engine starts it begins to rough idle until you turn it off.

    The gas cap is tightened.

    It has 245k miles.
     
    #4 AZaly, Nov 11, 2025 at 6:45 AM
  5. Brian1954

    Brian1954 Senior Member

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    Please provide a little history about the car. Has the head gasket or engine been replaced?
     
    #5 Brian1954, Nov 11, 2025 at 1:17 PM
  6. AZaly

    AZaly New Member

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    No, are those the primary reasons for the trouble codes?
     
    #6 AZaly, Nov 11, 2025 at 8:03 PM
  7. Brian1954

    Brian1954 Senior Member

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    A bad head gasket could be the cause of the rough idle and P0302 code. How is the engine coolant level in the plastic reservoir? Have you added coolant? How long have you owned the car?

    A bad head gasket will allow coolant to seep into the cylinder (usually cylinder #1 or #2) and cause misfires. This is a very common problem with the Gen 3 engine in the 150k+ miles range. The symptoms start out as a rough cold startup for a few seconds, and then the engine smooths out and will run fine the rest of the day. The symptoms will gradually get worse, and the coolant level will gradually go down in the plastic reservoir.
     
    #7 Brian1954, Nov 12, 2025 at 8:52 AM
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  8. ChapmanF

    ChapmanF Senior Member

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    Not to my mind.

    Misfiring can have a lot of causes, but before trying to delve into those possibilities, I'd probably look for the source of the gross leak into the fuel evap system (which could also be the cause of the incorrect purge flow). Then see if the misfiring is still a thing.

    Funny that the scan app is showing the codes as 'historic' if they are coming right back.
     
    #8 ChapmanF, Nov 12, 2025 at 8:53 AM
    Last edited: Nov 12, 2025 at 9:01 AM
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