2012 gen 3 head gasket repair. P0016 and cannot clear "check hybrid system. Maintenance required"

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Louhazosc, Jul 17, 2025 at 10:29 PM.

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  1. Louhazosc

    Louhazosc New Member

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    2012 Prius
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    One
    Hey guys,

    Did a head gasket repair. Everything went fine except the one thing I didn't like was every time I'd go to put the tensioner in, it would release before being seated. After a few attempts and pressure i got the bolts on but it was fully released.

    I had the engine set to top dead center, timing marks lined up etc.

    Did a hard reset disconnecting the battery and orange plug. Wife drove it today for 60 miles with no issue. then got a P0016 code - cam and crankshaft not aligned. So I replaced both the cam and crankshaft sensor cause I did hit the valve cover with some brake fluid. Also cleaned the MAF sensor while I was there.

    Now we have nothing. It continues to say "check hybrid system. Maintenance required" Did another hard reset. Battery disconnected, plug out. No good. It actually rattled for a few seconds and immediately shut down. No idea what the rough rattle was.

    So....do I go back in and start over? I really just don't wanna take all that apart and see the timing chain is just fine. Lot of work but I will. Can't think of anything else.

    Also had an issue with our fixd code reader so wasn't able to clear the p0016.

    Im lost at this point

    extra info: 200k miles. Car was sitting for 7 months. New tank of gas. head was machined and cleaned and valves resurfaced. New water pump, thermostat, timing chain, tensioner (but released as stated), cleaned egr, air intakes, new orings...all the things you do on a head gasket.
     
    #1 Louhazosc, Jul 17, 2025 at 10:29 PM
  2. Tombukt2

    Tombukt2 Senior Member

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    What is it the timing folks around correct every like 9 turns or someting like that so move crank from timing marks lined up until they come round lined up again ? How many turns ? Or does it align ?
     
    #2 Tombukt2, Jul 18, 2025 at 6:34 AM
  3. Tombukt2

    Tombukt2 Senior Member

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    I have the timing code right now on gen 2 it's 500K and chain in sure stretched. Oh well . On our gen3 we had no issue with chain popping out pin at install that I know of.
     
    #3 Tombukt2, Jul 18, 2025 at 6:36 AM
  4. ASRDogman

    ASRDogman Senior Member

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    Check the connections to make sure no pins are bent, wires broken, or not being connected properly.
    Are they Toyota sensors? Or parts store ones?
    You don't have to remove the timing cover to check the timing chain.
    Put the engine at tdc and check that the cam sprockets are in the correct position. You won't see the different
    colored links unless you get super lucky, or rotate the engine up to 30 times to get them to align.

    You need a code reader that will clear the codes. Disconnecting the battery for 30-60 minutes might clear them.
    But if you got those codes before replacing them, I doubt either were bad. Though carb cleaner is the worse you
    can use to clean them. It's always best to use the proper cleaner...


     
    #4 ASRDogman, Jul 18, 2025 at 8:56 AM
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