P0AFA for car sitting over a month

Discussion in 'Gen 2 Prius Main Forum' started by ids381, Nov 18, 2018.

  1. ids381

    ids381 Junior Member

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    Hi Prius community.

    I have code p0afa for a Prius that has been sitting for a long time. I checked all the cells are showing 7.3 ~ 7.4 all 28 cells using volt meter .
    When I try to start the prius it show P0AFA code.. only fan seem to be running. Any idea.. is 7.3 too low . I have the turningy charger but didn't t know if this is too low or what..


    Thanks for your help.

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  2. kens97uber171

    kens97uber171 Active Member

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    Not sure if that's too low to start. But if you have the charger. You can charge each cell or to speed it up charge a block at a time.
    You can do this from inside the car.
    Leave the bus bar that's towards the rear of the car connected. You will need to connect the safety connector to link the block it separates. Remove the bus bar thats towards rhe front of the car and xonnext your charger to the blocks on thar side.

    Can also remove the batter and do it that way. Easier if your going to charge each cell.
    Make sure your 12v batter I'd good too.. that can prevent a start... And other weird behaviors.

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  3. PriusCamper

    PriusCamper Senior Member

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    Yea... You're right at the edge of not enough power... You could have other problems too... But low voltage is the first thing to deal with...

    Since you have the pack out and the bus bars off, it'd be good to buy an IMAX B6AC V2 smart charger or any other kind of NiMH battery smart charger for RC cars, boats, etc., which is what we most commonly use.

    If you have time after they're all fully charged up to wait a day or two to confirm all modules are self-discharging the same amount of voltage and you don't have one that discharges faster that would be wise. Another option is load testing each module which means measuring voltage loss of each module after 2 minutes of hooking it up to one of your car's headlight bulb.

    Also could be a good time to do reconditioning on the modules so you don't have to pull it out again for a while. If you buy a prolong conditioning system you don't have to buy the IMAX NiMH smart charger and do module at a time but can do the whole pack... Learn more here: FAQ
     
  4. ids381

    ids381 Junior Member

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    A few days with the car in my driveway i am also getting P0AA6 + P0AFA

    I borrowed a friend's Hybrid battery and my car starts up ok and no faults, So i guess the issue is with the battery alone.

    I removed my Battery's Bus bars and cleared the copper plates, they were dirty like i have never seen before, i cleaned the plates and nuts but the isolation fault is not going away.

    Finally i got my hobby charger so i will try to charge the cells,

    Any idea about the Isolation fault ?
     
  5. PriusCamper

    PriusCamper Senior Member

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    There's a guy on here who wired up his 28 modules in parallel rather than series so he could charge the whole pack with just one 8.2v hobby charger.

    One of the smarter commenters on here who rebuilds packs said this type of wiring can "open up a can of whoopass" but never took the time to explain what they meant by that and myself and others who work on hybrid battery packs are still trying to figure out what he meant by that. We keep thinking about every detail of the charging process and have done all the math, but still don't understand what he meant by that. Sure wish he could explain what he meant?

    As for the POAA6, I'd wait to get the pack charged up first before you worry about diagnosing that. Of course if one module has self-discharged more than the others while it has been sitting there since your first voltage tests that needs to be addressed/replaced first. Also if you load test each module for 2 mins with headlight bulb after charging and track voltage drop at end of those two minutes you might be able to find a bad module that way too.

    As for the corrosion... Di-electric grease seems to prevent that. And if you want to buy some brand new thicker higher-quality nickel alloy bus bars for $60 bucks I can post the link to that.
     
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