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Yet Another Rough-Running Prius - Check Engine Light Lit

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by Michael Cerkowski, Nov 17, 2019.

  1. QuantumFireball

    QuantumFireball Active Member

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    Yes, the wiper arms and scuttle need to be removed to access the plugs, but it's not exactly 10 hours work either...
     
  2. bisco

    bisco cookie crumbler

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    i wouldn't spend the money on more than one thing at a time. there's no reason to suspect plugs, coils or egr system.
    i would start with the throttle body and work my way down the list. guessing can be an expensive way to repair a vehicle.
    the dealership should be able to read the codes and subsides, and with the service manual and an experienced hybrid tech, come up with the proper solution at a reasonable cost.
     
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  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Is the engine coolant level in the reservoir stable, not dropping?

    Judging from those codes, head gasket failing? On the other hand, considering the low miles, and a Plug-In which runs the engine less, very puzzling.

    Maybe look into "lead-down test". In this case, each piston (in turn) is brought to Top Dead Center in the compression stroke, then compressed air is connected via the spark plug hole (with a special leak-down test gauge set), the cylinder is pressurized, the gauges are observed for clues, and (equally important) the tester just looks around, anywhere the compressed air might leak out. This gives clues as to how the head gasket is leaking, from where to where.

    (Eric the Car Guy has a good video on this. He has trouble with his (new) gauge set, but nevertheless explains it well.)

    Another thing: remove the wiper and cowl, spark plugs, and have a look at the cylinders (with borescope). If cylinder number 1 and 2 (*) look exceptionally clean, that might be due to coolant leaking past the head gasket, getting into cylinder. If you can see pooling coolant, that would be the smoking gun.

    For cowl removal watch @NutzAboutBolts spark plug video, pinned in third gen maintenance forum.

    3rd gen head gasket failures are occurring with tedious regularity between cylinders 1 and 2, fwiw. Typically with much higher miles, and with neglected/clogged EGR systems.

    * Standing at front of car, the cylinders are numbered 1 through 4, going from left to right.
     
    #23 Mendel Leisk, Nov 19, 2019
    Last edited: Nov 19, 2019
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  4. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    How in the world does a 5-year-old car with 30,000 miles on the clock even come CLOSE to needing plugs or coils?
    Especially a PHEV?
     
  5. bisco

    bisco cookie crumbler

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    might be a first here, but something is wrong. from little use is my guess, but who knows, maybe just a defective part
     
  6. Michael Cerkowski

    Michael Cerkowski New Member

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    I certainly hope it isn't the head gasket. I'll look at the coolant reservoir. But wouldn't a bad head gasket produce serious misfires at more than just idle, with a little at about 45MPH?
     
  7. vvillovv

    vvillovv Senior Member

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    Most of us here are going on what we have seen posted here or their own personal experiences.
    There are not many of either with the 16 PiP, so far anyway.
    Closest thing with misfires, usually with Gen3's is, you guessed it and in substantial quantity from what I'm reading here at PC
     
    #27 vvillovv, Nov 19, 2019
    Last edited: Nov 19, 2019
  8. Michael Cerkowski

    Michael Cerkowski New Member

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    The coolant reservoir is where it's supposed to be. The dealer will be trying to diagnose it tomorrow. They claim to have already serviced the throttle body properly.
     
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  9. Michael Cerkowski

    Michael Cerkowski New Member

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    And the winner (we hope) is: defective ECU! Apparently Toyota is aware of this issue, and there is a TSB for cars that exhibit rough idle. The first step, which they have done, is to reprogram the ECU. If the issue recurs, they will replace the ECU - for free. Apparently Toyota has quietly extended the warranty on the ECU to 8 years. So no charge for this. We did pay about $200 for the fuel system cleaning a few weeks ago, so hopefully the car is fixed. We may never have had any symptoms due to old gas, but from now on we're going to "fill" it to only about 3/4, and try to use the whole tank every month or so.
     
  10. bisco

    bisco cookie crumbler

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    congrats, i hope thats it!
    up to six months is okay, i only put in three gallons at a time, unless i'm going on a long trip.
     
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  11. Michael Cerkowski

    Michael Cerkowski New Member

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    Today the check engine light came back on, so she brought it back and left it. She says they were also trying to walk back saying the ECM was still under warranty. They are $300 aftermarket, so who knows the cost of the part at a dealership, plus labor? I guess we'll find out. I'm also fairly sure that we're going to not get another ICE vehicle. For our retired lifestyle an EV does the job better and cheaper. I got my 40kwh Leaf in April of 2018 and all I've had to do to it is one $25 service and swapping on the wheels with snow tires.
     
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  12. bisco

    bisco cookie crumbler

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    i hear you brother (y)
     
  13. Michael Cerkowski

    Michael Cerkowski New Member

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    Has anyone had this unit replaced by a dealership? How much did it cost?
     
  14. Michael Cerkowski

    Michael Cerkowski New Member

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    We just had a "friendly" (not really) chat with the dealership's tech - one of them, anyway. According to her, they have consulted with Toyota, and have been instructed to essentially do a compression test and inspect the valve springs - for $480. She claims that either a valve spring or two is bad (???) or "the whole engine needs to be replaced." I cannot, for the life of me, envision a scenario in which broken valve springs cause a problem only with cold starts and idling, or a scenario in which this behavior necessitates that the whole engine be replaced. There was no more mention of the ECU, despite the fact that an ECU reset eliminated the symptoms for a while. I know how ICEs work. Is the Prius 's simulated Atkinson cycle engine so different that what this tech is saying can be true? Does anyone here know of an existing issue like this? Does anyone know of a good shop in the Albany NY area that specializes in Priuses? I have no confidence in this dealership...
     
  15. bisco

    bisco cookie crumbler

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    i would call toyota customer service, lodge a complaint, and ask for goodwill warranty help.
    you have a 6-7 year old car with 30k on the clock, and less than that on the engine. something doesn't add up

    did you buy it from this dealer?
     
  16. Michael Cerkowski

    Michael Cerkowski New Member

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    No, IIRC we had to struggle to get one of the last ones during an end of model year lease sale and another dealer got one from out of state for us. It has been serviced there since new, though. Anyone have that phone number or a contact url?
     
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  17. bisco

    bisco cookie crumbler

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    it is in your warranty booklet, or you can google it
     
  18. Michael Cerkowski

    Michael Cerkowski New Member

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    I wanted to make sure it hadn't changed in 6 years. I think we'll go another route anyway, if possible: if they have a written contact form, that is how we'd prefer to do it, as there is a record of what is said. My housemate has been a loyal Toyota fan for many years (Volvo before that) but they are quickly losing her.
     
  19. bisco

    bisco cookie crumbler

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    She’s not the only one
     
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  20. Mendel Leisk

    Mendel Leisk Senior Member

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    I went through this disenchantment process about nine years back, with Honda. Maybe they're all cutting corners, it sure feels like it... :cautious: