2005 Prius Cooling Problems

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by IHaveShirts, Apr 14, 2017.

  1. IHaveShirts

    IHaveShirts New Member

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    Hello all. I've been having an issue recently with the cooling pump. When I get the diagnostics done, it gives me code P2601. The car does overheat after about 2-3 hours of driving it. I've also read online that the way to check if the pump is working is to open the reservoir if you can see the liquid moving, its working. The liquid is moving but it still says its over heating. I've had the car for about 7 months now and I've never heard the fan in the battery compartment in the back turn on until now since it says its over heating. I did also get the battery pack changed with-in the past week since I'm assuming it was overheating before but never told me it was.
     
  2. andrewclaus

    andrewclaus Active Member

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    P2601 refers to the CHRS pump, which will not affect engine cooling.

    How is the car telling you it's overheating?

    Have you been checking engine coolant level?

    Which liquid are you looking at to see motion? About the only place to do that is in the inverter reservoir, which has nothing to do with the engine coolant or the code you're getting. The Prius has two separate coolant loops with separate pumps.

    The hybrid battery cooling system has nothing to do with engine or inverter cooling, and does not have liquid coolant or a pump.

    Do I understand that you recently changed the hybrid battery, and since then the battery fan has come on and never did before? Where did you get that battery and what kind of warranty do you have on it?
     
  3. edthefox5

    edthefox5 Senior Member

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    I think your pretty mixed up.

    P2601 refers to the CHRS the "coolant hot water recovery system" which is under the front drivers side headlight. It has measured the pump and the pump is not turning. Really common issue.
    It is an insulated thermos with a pump that stores hot engine coolant and then when your start the car it pumps that hot collant back inot the engine to meet emiisions quicker. A hot engine makes less emissions. BTW, in Europe cars they omitted that CHRS pump.

    Your checking the Inverter Coolant pump reservoir which has nothing to do with the engine coolant. That pump cools the Inverter and the transmission.

    And the battery fan has nothing to do with either pump really. 2 separate things...engine overheating and battery fan meaning the battery pack is overheating usually first sign of a failing battery pack. I suspect your not getting ALL the codes read properly. The OBD scanner must be Hybrid Capable P2601 is not a hybrid code .

    If car is overheating its usually the mechanical water pump bolted to the front of the engine. Its probably bad and leaking coolant out of its weep hole. get a flashlight and with engine off look closely on the front of the engine the passengers side for bright flecks of green which is dried coolant which is coming from the water pump weep hole. Very very common. Then take the top black plastic cover off the top of the radiator so you can take the radiator cap off and check its level. I bet the radiator is bone dry.

    You can only overheat that Little aluminum head motor once or twice before it will blow its head gasket $$$$ so get r done..
     
  4. IHaveShirts

    IHaveShirts New Member

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    I'll rewind a bit. About 2 weeks ago, I was just driving and all of a sudden 4 lights came on, big red exclamation, mark a little yellow exclamation mark, check engine and the VSC light. When they tested it, it gave them like 11 different codes but the car itself was working perfectly for a while until the battery stopped charging. I got the battery pack replaced. Car worked great for a day, drove about 90 miles and no lights at all. I go to work the next day and I drive a lot so with-in 3 hours of almost constant driving the same exact lights came on. I brought it back in and this is the code that it is giving them now.


    Ever since I've had the car and I've also talked to other prius drivers, none of them have ever heard the fan in the back near the battery pack turn on. The fan isn't always on, it only turns on when the lights come on after about 2-3 hours of driving it.

    I did check the radiator fluid and it was bone dry. I refilled it to the F line. I will try driving it around tomorrow to see what it does again.
     
  5. JC91006

    JC91006 Senior Member

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    If your fan is turning on in the back when you have warning lights, you should have a hv battery issue. That's used to cool the battery that the ECU detects has a problem. Who sold you the battery?

    The radiator dry is another thing all together
     
  6. edthefox5

    edthefox5 Senior Member

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    The fan is always on in the back But very low.
    When it's on so loud you can hear it the hybrid battery is failing. Thats what one or more of the 11 codes it threw was trying to tell you. But for some reason you focused on p2601.

    lately there has been literally hundreds of posts about failed hybrid battery's and all have the fan running loud in the back. Time for a new battery, do some research there's thousands of posts about it now.

    And also like II said you have a leaking failing engine water pump. Standard water pump just like every car ever made has.
    In addition to the bad hybrid battery and probably other issues. I would imagine it's mileage is over 200000 miles but who knows you never mentioned. The high dollar focus is the hybrid battery which is expensive.
    So before bothering about the water pump focus on that as the car may be totaled if very high miles.
     
  7. IHaveShirts

    IHaveShirts New Member

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    The car had 90k miles on it when i got it in october 2016. It now has 119k miles on it.

    Why exactly would a brand new battery with warranty be failing? Its not a refurbished battery but brand new.

    The reason why that code is being focused on is it was part of the 11-15 codes that showed up when the battery pack took a dive. Other codes were the A/C not working, transmission wasn't working and a few other codes that if they werent working, you would know but they WERE working. The transmission was just fine, no slipping and the A/C was pumping out cold air with no problem. After the battery was replaced, p2601 kept coming back. They said its the water pump. Its not the water pump, there is turbulence in the reservoir for it.
     
  8. andrewclaus

    andrewclaus Active Member

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    There's some confusion about the turbulence in the reservoir. The only place to see this is in the inverter reservoir, and this has no connection to the engine or P2601. And is that the reservoir that was dry?

    Have you been checking the level in engine coolant reservoir, up front near the grille? There would be no turbulence in that, except in extreme overheat conditions and you wouldn't want to be near it then.

    The Prius transmission is a CVT, and would never "slip." No gears actually "shift." Fault codes could deal with a failing motor-generator, for example, and you would not "feel" that until failure caused it to stop.

    The only reason the battery fan would be on is one of the thermistors in the pack is sensing excessive heat. The new hybrid battery is overheating, so you apparently have a bad one. Or a problem in the transxle is drawing excessive current, but that's unlikely.
     
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  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. The Prius has two separate coolant loops: a) engine and b) inverter/transaxle
    2. Therefore, there are two separate coolant reservoirs: the one next to the inverter is for the inverter/transaxle. The one behind the radiator is for the engine.
    3. Which reservoir was empty? I am assuming it was the engine coolant reservoir behind the radiator.
    4. If my assumption is correct, did you check the radiator fluid level in the radiator itself?
    5. To access the radiator cap, you need to remove the large black plastic panel over the radiator. It is held on with six plastic fasteners. To remove a fastener, rotate the fastener with a Philips screwdriver while exerting upwards pressure on the panel.
    6. Remove the radiator cap and fill the radiator to the top.
    7. If you find that the engine coolant was depleted, the most likely reason is that the engine coolant pump is leaking fluid. Look at the pump pulley, if you see a pinkish or whitish powdery stain, that is dried coolant leaking out of the pump bearing. This can often be seen as a deposit on the air conditioner compressor housing below the coolant pump. In bad cases the spray will deposit on the sound insulation pad on the underside of the hood.
    8. Where did you get the new traction battery from: a Toyota dealer, or some other source?
     
  10. IHaveShirts

    IHaveShirts New Member

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    The reservoir behind the radiator was completely dry, I filled it up last night when I went to go check it. The reservoir next to the electric motor is up the the full line and that is the one that I thought was having the problem but its not.

    Here is another odd thing I've noticed, when I have the windows open while driving 35mph+ i can hear like a rattling sound from the back battery compartment. Kind of sounds like its coming from that vent on the back seat but I cant exactly climb back there to find out where exactly its coming from while driving. I'm taking it back to the dealership that I got it from on Tuesday to install the new pump and possibly a new fan back there but they are going to take it apart to see if it needs it or not. The fan they said was about $100 but that might not even be installed but the new pump was going to be about $50. They are doing that based on the code that it keeps giving them even after they reset the code, i take it for a test drive and that code comes right back up again.
     
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Did you check the fluid level in the RADIATOR?
     
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  12. IHaveShirts

    IHaveShirts New Member

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    Yeah the radiator is full.
     
  13. andrewclaus

    andrewclaus Active Member

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    Your primary concerns should be 1) where did the coolant go, and 2) why does the battery fan come on. The two tasks you're planning have little or nothing to do with these concerns.

    The installer of the new hybrid battery should have cleaned the fan. There's no need to install a new one if the existing one is blowing. Check and see if it's dirty.

    The CHRS pump has nothing to do with engine cooling or coolant loss, but it could have been damaged by low coolant. Fix the leak, then work on the pump.

    Do you know that a full reservoir does not mean the radiator is full? The radiator will siphon coolant from the reservoir only after a heat/cool cycle, and if there's a large leak, the siphon may not work at all.
     
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  14. IHaveShirts

    IHaveShirts New Member

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    Well it wasn't what I was thinking. It didn't need a new fan back there. It did need a new pump. When they replaced the battery pack, they somehow managed to mangle/destroy the tubing that is used to cool the battery pack in the back. Drove it home and none of the lights are on, they would have turned on after seconds of driving it. I'm very excited to have her back!
     
  15. andrewclaus

    andrewclaus Active Member

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    Did the dealership install that battery and botch it that badly? Is this a Toyota dealer? The cooling air ducts are extremely simple. I don't even remember connecting them when I've done battery work they're that mindless. I guess that explains the rattling sound you mentioned earlier, too.

    Hopefully you got some work done at a deep discount after that error.
     
  16. jdenenberg

    jdenenberg EE Professor

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    Errors happen. My wife still is angry at my dealer. He installed a rebuilt HV battery for me and it failed due to his not clicking home a connector when we were 900 miles from home. It cost us an overnight stay in a motel and $40 for the repair in Indiana (refunded by my dealer).

    JeffD
     
  17. IHaveShirts

    IHaveShirts New Member

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    Sigh. New water pump installed, drove perfectly fine for 100+ miles. Next day I turn the car on and the check engine light is back on which I knew it would be. Took it to a certified Toyota mechanic, code is P2601. None of the extra lights were on before since I know when its going to overheat, I don't let it get to that point. He also tested the wiring to it and it seems fine. He tested the pump himself and it works fine. No one seems to know what the problem is. I've been out of work for almost a month now and its getting irritating to say the least.
     
  18. jdenenberg

    jdenenberg EE Professor

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    It is most likely that some air is in the cooling loop for the engine that is causing the pump to lose its priming. See if there is turbulence in the coolant reservoir when your Prius is in "Ready".

    JeffD
     
  19. IHaveShirts

    IHaveShirts New Member

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    Yeah there is turbulence when the car is idling.
     
  20. jdenenberg

    jdenenberg EE Professor

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    Check your thermostat for proper operation. If it is stuck closed, the engine will overheat.

    JeffD
     
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