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2005 Prius Air Conditioner Failure

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Shu65, Jun 10, 2018.

  1. Shu65

    Shu65 Junior Member

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    The air conditioner in my 2005 Prius quit blowing cold air yesterday while driving, and some warning lights illuminated. (See attached photos) The fan was still functioning, it was just blowing warm air. The car continued to run fine while I drove it for 10 more minutes to get it home and park it. I hooked up a recently purchased Memoscanner U480 CAN OBD2 to it and it read no error codes. (I'm now researching which Mini VCI to get.) Today I started the car and the AC seems to be blowing cold air again. Just curious if anyone has had this type of malfunction and can suggest an initial course of action. Thank you.
     

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    #1 Shu65, Jun 10, 2018
  2. SFO

    SFO Senior Member

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    Sounds like the inverter coolant pump could be going out.

    Check the inverter coolant pump for vibration, and or look in the inverter coolant reservoir for turbulence on the liquid surface while the vehicle in powered.
     
    #2 SFO, Jun 10, 2018
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  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The photos provided by the OP do not show the ABS/VSC/BRAKE lights on, which I would expect to see if the inverter coolant pump had failed. However it is easy enough to verify the pump's operation per post #2 above. The pump should be running whenever the Prius is IG-ON or READY.

    Since the check engine light is on, there is at least one powertrain diagnostic trouble code logged, having to do with the engine. Further, the MFD upper left corner displays the warning icon of the car with ! superimposed, which indicates a hybrid drivetrain problem (might be something in addition to the engine issue).

    I encourage the OP to get Toyota Techstream (or clone) to determine the trouble codes.
     
    #3 Patrick Wong, Jun 10, 2018
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  4. Shu65

    Shu65 Junior Member

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    Thank you for the suggestions, guys.

    The air conditioner is definitely working again. (Perhaps the computer logic shut it down yesterday due to increasing engine temps? I'll try to change the title of this post from "2005 Prius Air Conditioner Failure" to something more appropriate.)

    With the engine running there is no movement in the inverter coolant reservoir (which I assume is indicated by the red arrow in my attached photo). My DVM indicates almost 14v available at the electrical connection to the inverter/converter and transaxle coolant pump (in area of yellow arrow, if I'm reading my Haynes guide correctly), and I assume this is the pump that's supposed to be moving this coolant. I changed that pump at 100k miles (almost 83k miles ago).

    Also, the coolant fan doesn't come on, but I assume that's because the engine isn't getting hot enough to turn it on just sitting in my garage.

    Patrick, the Haynes manual's name for this pump indicates that in addition to cooling the inverter, the coolant is used for the transaxle, which I assume is part of the drive train. Maybe this pump failed, allowed the transaxle to get too hot, and resulted in the check engine and "!" warnings?

    Do you think I caused any permanent damage continuing another 10 minutes (with about 4-5 minutes at freeway speed) to get the vehicle home?

    Thanks again for your replies and suggestions, guys. I have a commitment that will prevent me from working on this for almost 3 weeks, so it will be sitting in my garage until then. I'll try to acquire Techstream by then, and then I guess I'll change the pump again.
     

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    #4 Shu65, Jun 10, 2018
  5. bisco

    bisco cookie crumbler

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    probably not.
     
    #5 bisco, Jun 11, 2018
  6. Shu65

    Shu65 Junior Member

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    Today I changed the inverter coolant pump which indeed had failed. Car is now running fine without any warning lights. I did buy a "Mini VCI J2534 TIS Techstream Diagnostic Cable for Toyota Firmware V1.4.1 (Newest Version)" from "luckybuy11", Jack Li, on Amazon. I am in the process of installing the software but it's a slow process with tech support being 12 time-zones away. Hopefully it will make future diagnoses easier. Thanks again for your videos and posts, Patrick. I referenced one again today when changing the pump.
     
    #6 Shu65, Jul 5, 2018
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