Replacing Hybrid Battery Fan - DIY or Dealer??

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by mfs1011, Jul 20, 2014.

  1. mfs1011

    mfs1011 Junior Member

    Joined:
    Dec 9, 2009
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    Location:
    Okehampton, Devon UK
    Vehicle:
    2007 Prius
    Model:
    N/A
    Hello from Devon in the UK

    My 07 Gen2 has 145k on the clock (miles not kilometres since we're talking the Queen's English) and has been showing error messages - triangle, obd and brake. I took it to the local dealer and got two error codes:
    a) Hybrid Battery ECU b) Hybrid Battery Fan

    So in light of the car's high mileage and age the dealer agreed to fit a salvaged ECU which came out around £600 ($1000) cheaper fitted than a new part. I sourced the part on Ebay from a salvage company in MN and it was duly fitted.

    With hindsight I may have done better to look in Germany as I would not have had to pay 20% Value Added Tax but, hey ho.

    Anyway, the warnings are still popping up, so I am left with one more throw of the dice before concluding its the HV battery that's behind all this. I need to replace the fan.

    So Toyota are quoting £300 * ($510) for a fan but I can find them for around $50 on Ebay. It's a relatively accessible part to replace.

    My question (finally got round to it) is this: Does the ECU need to be reprogrammed if I swap out the fan? In other words can I do this or does it need to be done by the dealer who will charge $70 just to plug it his laptop?

    For background:
    a) I've been using Android Torque and monitoring battery voltage. Thus far I cannot see any failing cells - the voltage output is pretty uniform. There is little difference between highest and lowest voltage

    b) We've been having some hot weather in the UK (at least by our standards) and it does appear that heat is an issue, at least in terms of the frequency of when the errors pop up once the code has been cleared.

    Thanks for all your help and suggestions.
     
    #1 mfs1011, Jul 20, 2014
  2. Prius_Cub

    Prius_Cub Member

    Joined:
    Feb 12, 2013
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    Location:
    Radford, VA
    Vehicle:
    2008 Prius
    Model:
    II
    No need to flash anything, though after the new fan is installed, if you do it yourself, I highly recommend using the PID's for Torque that adds the functionality to set a desired speed level for the fan or Mini VCI w/ Techstream can accomplish the same thing with a diagnostic test that let's you run through all available speed levels. When doing the swap out, the 12v battery should be disconnected, which will clear the code anyway. But do make sure the fan is working before putting everything back together. Good luck!

    HTC Evo 3D
     
    #2 Prius_Cub, Jul 20, 2014
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  3. nh7o

    nh7o Off grid since 1980

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    Location:
    Hawaii
    Vehicle:
    2009 Prius
    Model:
    II
    It sounds like the dealers in the UK are just as ready to throw parts at a car with no real expectation of a fix, as in the US. Too bad about the ECU replacement. To my admittedly limited knowledge, the battery ECU has never conclusively been shown to go bad, although there is always a first time. It is easy to swap out, so techs will do so, but without real insight.

    In any case, a very few minutes spent with a voltmeter and the schematic would easily tell if the ECU is putting out fan power, and if the fan is actually working. The fans are known to get quite dirty in certain instances, so perhaps just a good cleaning is all that is needed. One can hook the fan to a 12V source and determine if it turns properly.

    IMHO, I would not go back to that service center. It is easy DIY, with good youtubes and photos on this site. So dive in and have your vacuum cleaner at the ready.
     
    #3 nh7o, Jul 20, 2014
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