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P0a0f-504

Discussion in 'Gen 2 Prius Technical Discussion' started by Dxta, Nov 24, 2018.

  1. Dxta

    Dxta Senior Member

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    Pls has anyone ever come across this kind of code before, while troubleshooting an engine failed to start problem on a Prius 2005, with 254,091miles?
     
  2. edthefox5

    edthefox5 Senior Member

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    yes ran out of fuel.
     
  3. Dxta

    Dxta Senior Member

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    The had 1/2 tank of fuel in it. So, I'm just surprised.
     
  4. Skibob

    Skibob Senior Member

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    You mean it said it had 1/2 tank. Don’t forget to add at least 3 gallons, or it won’t reset.
     
  5. Dxta

    Dxta Senior Member

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    I got another ECU, to try out with. The car could not start.
    The mg1 started briefly, and died within some seconds.
    Scanned the car, I got a different code:
    P0a0f-525.
    I have checked that code on alldata, but can't get anything.
    Has anyone come across this specific code?
     
  6. SFO

    SFO Senior Member

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    Normal behavior, mg1 spinning up the ICE and giving up when it won't start.
    Are you scanning with TechStream?
     
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  7. Dxta

    Dxta Senior Member

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    Yes, I'm.
    For that code, and checked that online, without success.
     
  8. edthefox5

    edthefox5 Senior Member

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    If you don't have a hybrid battery charger you'll soon run out of battery power cranking it over. Keep an eye on hybrid battery capacity with techstream as you continue to troubleshoot.

    With the engine not starting you should have a lot more codes than the one your posting. harvest & Post all the codes there will be many.

    If its not fuel and hybrid battery power ok I would look at the transmission. While you have someone ready the car watch the water pump belt see if the engine moves at all when mg1 spins. if mg1 spins up and no engine turning at all it may be a blown trans input damper.
    Not real common but have seen a few here over the years. Or the engine is seized. is there any oil in the engine?
     
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  9. Dxta

    Dxta Senior Member

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    Thanks for the replies ed! There are other codes truly, which I cleared initially, after replacing some parts.
    With that done, I was hoping, that would do the trick.
    I had carious codes ranging from p0012 to p0a0f 533, to what I ha e currently (p0a0f 525).
    I had checked the valve timing alignments, replaced can/Crank sensors, tested all electrical circuitry from the sensors to the HV ECU to established continuity and resistance (no open or short circuit problems).

    My plan was to swap an in erter to see what happens next.

    Yeah, the battery is done right now. I'm going to get it charged this week, and continue with the diagnosis.

    Thank you so very much for pointing me to the transmission/engine likelihood that it may have seized.

    I'd performed that test this week after charging the battery, and observe if the belt moves when I attempt to start it.


    Dxta
     
  10. Dxta

    Dxta Senior Member

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    There was oil in the engine. In fact, the owner mistakenly overfilled it by 1.5liters. I had to drain that extra oil from the sump.
    The engine rotates, when I was rechecking the valve timing on the engine.

    Are you saying in essence that if mg1 turns, and engine also turns, that might suggests that the input damper is bad?
     
  11. edthefox5

    edthefox5 Senior Member

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    The 533 is guaranteed ran out of fuel.

    If mg1 is spinning up the engine should turn over if only very very briefly. It should move. Watch the water pump belt. No turn over no connection to trans input shaft.
     
  12. Dxta

    Dxta Senior Member

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    Alright, would put that in mind when troubleshooting this week after charging the battery.

    What about if there's a turnover of the belt, and it still does not start?

    Definitely, I might still get an engine failed to start code.

    And would that be something related to the transmission too?

    PS: for the 533, I had to replaced the fuel pump, because was so low on pressure.
    That took care of that code though.
    Fuel was even more than half tank. That's the surprising thing about this whole thing.
     
  13. Dxta

    Dxta Senior Member

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    Hi @edthefox5 . thanks for your previous suggestions.
    Opened up the valve cover, and discovered the timing chain slipped of off the sprocket of the exhaust camshaft. That got the timing chain, loosened, and seized the engine. Valves on number one cylinder were bent.

    Decided to replaced the engine entirely, instead of carrying out repairs on the damages seen.

    Started the vehicle; it came on ready for some seconds, then went off.
    Showed checked hybrid system.
    Scanned for codes on the engine side, got nothing. While on the hybrid side, I got this code:

    P0a0f-205 engine failed to start.
    What could possibly be the problem why the ICE isn't kicking in as before, to charge the battery?
    I have replaced the HV ECU, and nothing has worked.
    I'm leaning towards the transmission system, maybe, mg2 has failed?
    Has anyone experienced this problem before pls?
     
  14. SFO

    SFO Senior Member

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  15. Dxta

    Dxta Senior Member

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    Yeah, have tried the old ECU, and still the same thing. ICE comes on for few seconds, then shuts down itself.
    No codes, apart from p0a0f 205 for now.
     
  16. SFO

    SFO Senior Member

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  17. edthefox5

    edthefox5 Senior Member

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    I think he replaced the engine in post #13.
     
  18. SFO

    SFO Senior Member

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    True, though sometimes small things are unintentionally skipped :whistle:
     
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  19. edthefox5

    edthefox5 Senior Member

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    He’s hard to follow.
     
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  20. Raytheeagle

    Raytheeagle Senior Member

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    I’ve given up trying:rolleyes:.

    Wonder what the next topic wil be:whistle:.
     
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