1. ChapmanF

    ChapmanF Senior Member

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    Part of the purpose here was to compare what you told me:

    to what the repair manual told me:

    [​IMG]

    The difference is that the repair manual states that only the engine shuts down, and the car remains otherwise powered and READY.

    The outcome matched what the repair manual says. The engine stopped, the car remained powered and READY.

    J0V is supposed to prevent a total-car power-off in the case of certain inverter failures, and make the car remain otherwise powered up and READY instead, with usable steering and so on.

    So it's easy to see the parallels between the two systems:

    Inverter failure w/MG ECU reset Overheat with pump code
    1 pre-J0V: total shutdown (no steering etc.) Azusa says: total shutdown (no steering etc.)
    2 post-J0V: car stays powered&READY (steering etc. still works) Manual says: car stays powered&READY (steering etc. still works)


    This car has had J0V done, and what this car did on overheat is what the manual already said it would do. Whether that has anything to do with J0V being done, or the overheating case was just already right and always did what the manual said it would, would take more doing to establish. But the manual (written before the J0V recall) has always said this case would be handled by stopping the engine while staying powered up and READY, and that is what happened here.
     
  2. アレン・スピクタロン

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    So the Prius indeed will let you know when the engine water pump stops working, i guess the same goes for the Prius C.
     
  3. ChapmanF

    ChapmanF Senior Member

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    Well, the point of this latest experiment was to see what the ECM does when it knows there is a pump issue (showing a check-engine light and code for it) and the engine reaches 105℃. It turned the engine off at that temp, which is exactly what the repair manual said it would do.

    You might still want to review post #28:

    So there's still an open question just what temperature has to be reached before the ECM complains, if it has not detected a pump problem.

    There was one type of pump problem a 2010 can't detect: when the water pump impeller breaks off and the pump spins too fast without really pumping water. They had not thought to provide a trouble code for "too fast". They added that in 2011. :)

    I assume because the c and v were born in 2012, they probably include the "too fast" code.

    I have not looked in the c or v repair manual to see if it says the shutdown behavior is the same for the P148F too-fast code as it is for the other water pump codes.
     
  4. アレン・スピクタロン

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    I see, maybe if you have the time, or you are able to, you could take a look at the C and V repair manual and see what is says about such thing, i would do it myself but i don't think i can find such thing online, and i can't pay techstream right now.
     
  5. JohnPrius3005

    JohnPrius3005 Member

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    ChapmanF, That was one helluva detailed, complex, impressive experiment you did to prove your point! I'm in total awe of your Prius knowledge. Brilliant. Thanks for sharing.
     
  6. ChapmanF

    ChapmanF Senior Member

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    I tend to kind of bank up questions until I have a bunch of them, and then I'll feed TIS another twenty bucks once or twice a year and try to remember all the questions I had and get the answers. So if I remember you had this question the next time I'm in there, I'll look, but that could be a while.

    There are some other members here whom I suspect of having their TIS subscriptions paid up more of the time, so maybe one of them will chime in.

    Thanks! One quibble: if I had known in advance what the result would be, you might call it proving a point, but in reality I didn't know, so it was a simple matter of wanting to find out. Naturally, in a question between the repair manual and Azusa, I would have given odds that favored the manual in any case, but (a) Azusa seemed very convinced, (b) while I'm mostly amazed at how few errors sneak into the manual for such a complex machine, there have been a few spotted from time to time, and the same for 'bugs' in the car, and (c) it seemed like something that would be worth really knowing. So it wasn't something I did to prove a point, but to find something out.

    There's no need for 'awe' ... I'm pretty happy to share where most of my Prius knowledge comes from. The $20 cover charge is very reasonable given all of the information that's there, including not only all the manuals but their technician training course handbooks and so on.

    There was a recent thread with a question about ways to get more general background and I tried to put some suggestions there too.
     
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  7. AzusaPrius

    AzusaPrius Active Member

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    So the engine shut off but car remained on?

    Did you see if you could drive it?

    When the engine shut down on mine there was no power to move it, it just coasted and there was no power steering, all dash lights were on.

    Now, what it should do is just run on the engine right?

    Did you get a overheat warning?

    I did not when mine shut down.



    https://plugoutpower.com/

    http://projectlithium.com/



    Home - Pulstar Spark Plugs
     
  8. ChapmanF

    ChapmanF Senior Member

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    Right, it did exactly what the repair manual says it does, which is stop the engine, and leave the car powered up in READY mode. Everything has electric power in READY, including the steering, and there is a short distance of low-speed electric driving available. When the car isn't a Plug-In or a Prime, the electric driving won't take you very far or very fast.

    It can't run on the engine, the engine is exactly what overheated and got shut down. It has only traction-battery power available.

    The warning situation was exactly this:

    • The ECM showed the check-engine light throughout the entire test, from the moment the ECM detected there was a water pump "problem". Reading the code from the ECM confirmed that was the problem detected.
    • The power management control ECU showed the triangle and a "CHECK HYBRID SYSTEM" MID message as soon as the engine had shut down. The code in the power management control ECU was P0A0F-206, which just tells you the engine won't start, because of an "engine component malfunction". That reveals that the power management control ECU doesn't really have any insider role in the decision to shut down the engine here. That's done by the ECM on its own, and the power management control ECU only finds out the ECM has decided to deny engine start requests for some reason.

    Driving in EV mode in normal conditions (with the engine available), I usually don't get more than a few blocks before the engine will be called on to start. I did not try to find out how far I could go with the engine unavailable. There is undoubtedly a limit, and no one should expect to get very far or go very fast. In any situation where the engine is lost and there's only traction-battery power, the goal should be "get out of traffic and off to the shoulder". Pure-EV driving in a non-PiP, non-Prime just isn't up to more than that, unless you see an obvious great turning-off place right up ahead.

    I did not get the red-thermometer light on the combination meter at any point during that test.

    An interesting piece of information that came out in another recent thread is that there are two engine coolant temperature thermistors under the hood. There's this one, that's wired to the ECM:

    [​IMG]

    And there's this one, that's wired to the combination meter:

    [​IMG]

    The one that's wired to the combination meter will give you the red thermometer light, if it hits about 248 ℉ (120 ℃).

    [​IMG]

    (Checked by faking out that thermistor with a potentiometer and twisting it till the light came on.)

    [​IMG]

    But note that the 120 ℃ setpoint in the combination meter to light that light is above the 105 ℃ threshold where the ECM shuts down the engine, when it knows there is a water pump problem. (We did establish back in #28 that the ECM does not shut the engine down at 105 ℃ if it isn't aware of a water pump problem. This is purely a safeguard that comes into play when the pump is known to be in question.)

    So it's not surprising that this engine shutdown occurred without the red-thermometer lighting up.

    Another reason it's not surprising is the location of that sensor that goes to the combination meter. The hose it's in is the return hose from the exhaust heat recirculation system:

    [​IMG]

    Coolant from the engine has to flow out a hose, down to the exhaust, and back up a hose, to reach that sensor, to trigger the red-thermometer light. If the water pump is really not pumping, none of that might even happen.

    The moral has to be: if the ECM tells you the water pump is bad, take it seriously. If you must drive, plug something in the OBD port and watch your coolant temperature. Don't wait for a red-thermometer light, and be aware that the threshold for engine shutdown changes to 105 ℃ and that's below where the red light would come on anyway. If you are driving and see 105 ℃ coming, expect the engine to stop. If the engine stops, and you are not in a Plug-In or a Prime, don't expect to go any faster or farther than your car as a pure EV can go.

    Really, running the engine at all with a bad water pump should be avoided if at all possible. As you can see in the test above, I wouldn't even do that for test purposes. Fake out the ECM so it thinks the pump is bad? Sure. Really run the engine without coolant flowing? Fuhgeddaboudit.
     
    #48 ChapmanF, Apr 3, 2021
    Last edited: Apr 3, 2021
  9. アレン・スピクタロン

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    Why would they even put that sensor that goes to the combination meter? seems like it serves no real purpose on letting you know that something is wrong.
     
  10. ChapmanF

    ChapmanF Senior Member

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    As long as the water pump is working, coolant is circulating, so that temperature sensor will have a representative reading.

    Your engine can overheat for other reasons besides a water pump failure. You'd still want to know about those. Really, water pump failure is a problem that's historically really rare (conventional water pumps weren't electric, they didn't have plastic impellers breaking off, as long as your belt didn't break they would always pump water even if they sounded bad or leaked some.)

    The goal should be to jump quickly on water pump codes and solve them right away (running with no coolant circulation is no way good for an engine), and that way water pump failure should be a very rare cause of our overheats also.
     
  11. AW82

    AW82 Member

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    Well, now that's been hashed out...I think I'm feeling safer about waiting a while before preventatively replacing the pump on my 2012 with 158k.
     
  12. ASRDogman

    ASRDogman Senior Member

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  13. ChapmanF

    ChapmanF Senior Member

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    I haven't, but I'd love to look at detailed photos of that next to an original....
     
  14. johnnychimpo

    johnnychimpo Member

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    I did. It melted. I'm having an issue where pumps get supper hot and fail. Engine is not overheating but pump is extremely hot that it melts the impeller. Currently I have a gen 3 with a gen 4 engine and have burned 2 gen 3 pumps. I currently have a gen 4 pump installed but I'm going to take it to a independent shop.
     
  15. johnnychimpo

    johnnychimpo Member

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    Now it worked but failed soon after was it due to being poorly made or my current burning pump issue. I mean my car should overheat and shut down before the plastic would ever get hot enough to melt. In any case I advise just by new and replace. You would kick your self if you went on vacation and your pump went out because you cheaped out on a water pump
     

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    #55 johnnychimpo, Aug 28, 2021
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  16. ChapmanF

    ChapmanF Senior Member

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    Is there any chance there's a flow restriction in your engine somewhere and the pump could have run while dry? I don't think they're built to take that very long at all (like, even to test one on the bench, I think I would arrange for it to be in coolant).
     
  17. johnnychimpo

    johnnychimpo Member

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    Let me go double check.
     
  18. johnnychimpo

    johnnychimpo Member

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    I checked but see nothing obvious, I checked the hose going to the cat and it was warm on the way to hot so I suspect flow is good back there. I have heat so flow is good there as well. the and I can feel heat from the small hose on the thermostat. Now the hose from the radiator always seem cold or barely warm. so maybe radiator issue. Of note I plugged in my other pump and it spins up on ready and when the engine is running. It seems to run all the time is that normal?? not sure at what speed its going but I let it run for a while and did not notice it getting hot so I am now leaning towards a flow issue.
     
  19. ChapmanF

    ChapmanF Senior Member

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    I think it's normal to run the pump (at some speed, not necessarily highest) at any time when the engine is running.

    Temperature deviations between any localized hotter and colder spots in the head or block are bad things, so part of the reason for always running the pump when the engine runs is not just to carry heat away but to keep it as even as possible throughout the engine. That's the reason running the engine pumpless even for a short time is no good (and the reason in the experiments in this thread I never really slowed down the pump, just intercepted WPO and WPI and sent the ECM a slowed-down signal so it thought the pump was slow).

    You can see how fast the pump is going in the data list in Techstream, or just hook a scope to the WPI circuit. If you don't have a scope but your multimeter has a frequency setting, that works. As seen in #39, the frequency in Hz multiplied by 30 is the pump rpm.

    Ever stuck your thermostat in a saucepan to confirm what temperature it opens?

    Is the thermostat housing/elbow by any chance different between 3 and 4? If so, which one is on there?
     
    #59 ChapmanF, Aug 28, 2021
    Last edited: Aug 28, 2021
  20. johnnychimpo

    johnnychimpo Member

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    What is this thing called and whats if for mine has it im thnking of replacing it. with the us version
    Anyone know where I can get the use version without the grey sensor
     

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