2005 Prius. Vibrations with Engine and Flashing check engine light

Discussion in 'Gen 2 Prius Main Forum' started by cthindi, Nov 15, 2019.

  1. cthindi

    cthindi Member

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    I have 2005 Prius with 365 K miles.

    Just today it developed a problem. It drives just fine with engine off. The engine does start and also provides power. It may not be as much as usual.

    However there are severe vibrations when engine is on even at engine idle. The check engine light flashes with engine on. I am not able to pull any codes and the light does not stay on consistently.

    I had replaced spark plugs about 40000 miles back. So those are still fairly new.

    For experts any idea what the problem could be?

    I am aware check engine light flashes with misfire and the symptoms could be a cylinder misfiring. But then I am not able to pull any codes with Scangauge. I also have Bluetooth adapter with Dr Prius App. I will check with those as well.
     
  2. SFO

    SFO Senior Member

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    Please post any known OBD2 DTCs.

    Did you clean or check the COPS for carbon tracking when replacing the plugs?

    When replaced, did you use locally purchased plugs, either from the dealer or an auto parts store?
     
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  3. cthindi

    cthindi Member

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    I had dealer replace the sparkplugs. But that was about 2 years back. There were no symptoms back then and I did not check anything myself. I have also replaced MAF sensor myself.

    I do not know how to check Coils for carbon tracking.

    I also have Techstream and will try to see if I can identify anything with that.

    Unfortunately that would have to wait until Sunday.
     
  4. SFO

    SFO Senior Member

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    Techstream would be best, but if you have a chance to use that bluetooth adapter and dr prius. Then post those DTCs also (y)
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    A flashing CEL is caused only by severe misfires, which also explains the shaking/vibration.

    At 40k miles, makes me wonder if iridium plugs were not used, or counterfeits.....
     
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  6. cthindi

    cthindi Member

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    I hope Toyota dealer service center would not be using counterfeit one's. But I was wrong about the mileage. I checked service history.

    It is 75000 Miles and not 40,000 and that was three years back. Still well below expected life. Other possibility could be ignition coils. I will know better later.

    I only hope it is reasonable amount to fix. Obviously with such high mileage I do not want to spend a whole lot of money on the car. As much as I love it, there will be some time to let it go.

    Spark plugs or Coils should be reasonable amount.
     
  7. ChapmanF

    ChapmanF Senior Member

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    75,000 miles is barely adolescence for a Prius
     
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  8. SFO

    SFO Senior Member

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    Seriously doubt it happens all that often, but one never knows : Spark plugs | PriusChat
     
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    75,000 miles on a set of plugs, although not quite 100k, is plenty. I recently had one go bad on my sons car because the small alloy metal chip that was bonded to the ground electrode had fallen off. Severe misfire on that cylinder. The gap on that plug had worn to 2x the limit, yet the other 3 plug gaps were still perfect.

    Don't get upset about the car. 95% chance you just need a set of plugs. $40 or less if you do it yourself.
     
  10. Classic_pri

    Classic_pri Former 2001 Prius 0wner

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    Yes, the gap will tell you a lot about the plugs' condition. Even an intermittent misfire should trigger a trouble code, though, IME. Wife's Prius had an occasional misfire that came from a bad fuel injector.
     
  11. TMR-JWAP

    TMR-JWAP Senior Member

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    But the car has 365k miles...now middle aged, lol...75k on the plugs..
     
  12. ChapmanF

    ChapmanF Senior Member

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    Heavens to Betsy, I missed that, right up there in the first post.
     
  13. cthindi

    cthindi Member

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    I got following codes.
    P0300 Random/Multiple Cylinder misfire Detected.
    P0302 Cylinder 2 misfire detected.
    P0304 Cylinder 4 Misfire detected.

    I will try replacing spark plugs first. Otherwise I may try replacing ignition coils as well.

    Someone I was talking to also mentioned problem could be with head gasket or with Fuel Injector. I know either fuel or Spark both can cause misfire. But headgasket? How likely is that? Would air fuel mix leak result in misfire? and would that start all of a sudden? I doubt that. Engine had never overheated in life, and I do not see any other symptoms.

    But if spark plugs and coils do not resolve the issue, I will have to bid adieu to my beloved Prius.
     
  14. SFO

    SFO Senior Member

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    Plugs should be fine, unless soiled. Take a look before buying/replacing.

    Look at the COPS for signs of arcing and carbon tracking. They might need cleaning or new rubber.

    Cheapest and easiest, would be to switch coils 2 and 4 with 1 and 3, and see if the misfires follow.
     
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  15. cthindi

    cthindi Member

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    Thanks. I will try that. Do you have any You Tube link or so how to do that?
     
  16. SFO

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  17. cthindi

    cthindi Member

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    I have good news to report.

    I replaced all 4 coils and spark plugs. The issue seems to be now resolved. Check engine light also reset automatically after driving a bit.

    I had driven the car about 25 miles with misfire. When I re-scanned with techstream I got misfire code for 3 cylinders. Thus I did not bother about swapping coils as I had initially planned, and replaced everything.

    I used aftermarket coils from amazon 45$ for set of 4. (
    )

    One thing I noticed that there was some oil on couple of spark plugs. While most had some on thread area, for couple of those, it was also on the ceramic. With that I was not very hopeful, thinking it could be head gasket that is failed. So keeping my fingers crossed.

    I did not see any incidence of carbon tracking on the plugs or on the coils. Spark plugs appear in good shape with no significant wear on any. On one I saw some whitish deposit on ground electrode. But I do not feel that should be cause for misfire. It could lead to hospot. But then misfire would not happen on a cold engine. Spark plugs are all Denso as replaced by dealer.

    I have driven 25 miles after the change and things look OK.

    Is there any way to check coils removed with a multimeter? I think two of the terminals would be a coil. What would be other two? Some way of detecting misfire? And if that is the case how does that work?

    I will anyway check all 4 with multimeter.

    Still keeping my fingers crossed. If there is something else having a problem, I should know in a week. So I am putting off tire purchase at least for a week. ( tires are at about 4/32 remaining).

    Thanks for all your help.
     
    #17 cthindi, Nov 23, 2019
    Last edited: Nov 23, 2019
  18. cthindi

    cthindi Member

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    Search on forum posts indicate there may be a valve cover gasket leak that got oil on plugs and coil.

    2007 Prius Oil On Spark plug.. | PriusChat

    I will check again after a few days if that needs to be addressed as well, unless experts suggest that is something that needs immediate attention.
     
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