OEM 2008 Prius Hybrid Battery Replacement

Discussion in 'Gen 2 Prius Main Forum' started by tarheelbuc, May 7, 2021.

  1. tarheelbuc

    tarheelbuc Junior Member

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    We have a 2008 Prius that needs the hybrid battery replaced. I can get it from a local Toyota dealer in a few days and will be replacing it myself.

    It is my understanding that these replacements are not just drop in and go. My question is what parts off the old battery do I need to swap out with the new battery from Toyota?
     
  2. alftoy

    alftoy Active Member

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    Some info in this discussion. TMR-JWAP has tips, Desert Flier just did the swap. See if he chimes in.

    HELP! Hybrid battery died. | Page 3 | PriusChat

    DO not forget to swap ALL your old parts to the new battery. The black plastic piece that slips onto the clamp bars is one that gets forgotten sometimes and will cause your battery to overheat by allowing air to flow out the electronics section instead of being forced down through the modules.

    Job complete. Very straight forward for those with some mechanical ability. I would not attempt this without using high voltage gloves. Toyota includes new internal high voltage cables, disconnect switch, and a few miscellaneous hardware items in case the old ones had corroded. Drove about 200 miles and averaged 45.3 mph with AC running so I'm happy with that. Thank you everyone for all of the advice and ideas!

    More OEM battery replace discussion, also replace instructions froma different supplier.

    Replacing the hybrid battery with a new Toyota battery | PriusChat

    Prius Battery Replacement Kit (GenII/GenIII) with NEW custom cells | PriusChat
     
    #2 alftoy, May 8, 2021
    Last edited: May 8, 2021
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  3. Prodigyplace

    Prodigyplace Senior Member

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    Also do not return the old core pack until you get the new pack working if you return the core with some parts you need then you have to buy them new again.
     
  4. tarheelbuc

    tarheelbuc Junior Member

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    Thanks for the links! I think I have read some of that but, it wont hurt it go back through it again. Battery isnt due till Wednesday so, I have a little more time to study up.
     
  5. ski.dive

    ski.dive Active Member

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    I would have the dealer install it, this way the work will be done correctly and you will have a great warranty.
     
  6. Prodigyplace

    Prodigyplace Senior Member

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    I believe dealer installed is 3 year warranty instead of 2. I doubt there have been any warranty failures anyway. Of course installation related failures are possible.
     
  7. tarheelbuc

    tarheelbuc Junior Member

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    Well, the battery came in Wednesday, picked it up Friday and started the replacement yesterday. This is not that tough of a job and the key is organization of all the bolts and pins. (or so I thought) Anyway, got it swapped out and before bolting everything down, I reconnected everything and tried to fire it up. It ran a few seconds before throwing two codes I had never seen before. P3191 P0A0F

    These codes were not present before but, they sure are now. After some reading, seems they are no start codes. MAF, throttle body and 12v battery seem to be everyone's suggestion to start with first. I will do that later today. My question is, if theses codes were not present before battery replacement, isn't it highly unlikely these codes are not related to the MAF, throttle body and 12v battery? Meaning if they were a problem, shouldn't or wouldn't they have showed up before?

    Kinda baffled on this one. Going to get some cleaner in a bit and see if that helps. My guess it wont but, never hurts to try.

    Any ideas?
     
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  8. TMR-JWAP

    TMR-JWAP Senior Member

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    got it swapped out and before bolting everything down, I reconnected everything and tried to fire it up. It ran a few seconds before throwing two codes

    First, make certain you have at least some of the case mounting bolts installed and tightened to ensure the case is properly grounded to the car body. Relying on the weight of the battery to make that continuity is not adequate.

    Second, the engine will spin for several seconds while trying to start, and will sound like it is running. Your engine never started, as evidenced by the P3191 and P0A0F. Did you disconnect the 12v battery at any time prior to or during the HV battery swap? this will cause any "learned" values in the ecus to revert to default values. The most common one to cause an engine to not start is the throttle body. This "idle-start" position is a learned value that changes a bit due to carbon buildup. If the default value is significantly different from the previous "learned" value, the engine may not start. Cleaning the throttle body of buildup will allow the actual "idle-start" position to return closer to the default value. It probably wouldn't hurt to also clean the MAF sensor. A brand new Toyota battery should be able to go through several engine start attempts before becoming too weak to spin the engine.
     
  9. tarheelbuc

    tarheelbuc Junior Member

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    Good evening and thanks I appreciate the suggestions. I spent the better part of the afternoon re-checking my work and everything seems to be as it is supposed to. I did end up taking the case back off when doing this and I did put a couple of bolts in the case on the backside (towards the hatch). I also cleaned the MAF and throttle body, put a trickle charge on the 12v. The gas tank was 98% full when I made the swap so I know its got plenty of gas. As one of the replies questioned, I did unhook the 12v battery while doing the repair. I did not remove the neg or positive at that time, I pulled the two plugs connected to the battery. This afternoon, I removed the ground for an hour or so to see if any of the codes would clear. I then hooked it back up and put a trickle on it for the hell of it.

    Put the safety switch back in, tried to start, same results.

    Another thing that I noticed when the motor tries to fire, it sounds awful rough. Feels like the engine is shaking. Never heard or felt that sound at anytime in the previous 13 years.

    Im done for the day thats for sure and guess I will go back and do some research and reading before starting back at it tomorrow after work. Again, thanks to those who offered help!
     
  10. TMR-JWAP

    TMR-JWAP Senior Member

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    If the engine is spinning, then you did fine on the HV battery work. If the engine is spinning but not starting, there is something else going on, unrelated to the HV battery.

    The engine needs air, fuel and spark. One of those is not adequate.
     
  11. ColoradoCrow

    ColoradoCrow Junior Member

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    Hmmm. How long has it sat? Is your 12v battery more than 2 years old? Did you do the self check on the MFD screen to read the voltage? How many miles were on the car when you had the Hybrid battery die?
     
  12. jkisf

    jkisf Junior Member

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    Strange all the battery swap videos I've seen that went smooth had erased all codes. I was thinking this was a simple changeover and hardest time consuming part removing all the interior pieces. Following this thread as I am attempting a battery swap from the dealer as well.
     
  13. tarheelbuc

    tarheelbuc Junior Member

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    It is a pretty simple changeover. Don't be discouraged by whatever is going on here. If you have any common sense and two good eyes, you can do it. Take pictures of the old and new battery before starting and lay everything out organized as you go. Youtube is your friend. Cannot tell you how many hours of videos I watched to make sure I did not screw up. Went and re-watched some of them yesterday to make sure I did not miss something.

    Car has sat for 10 days as of today. 12v battery was checked on the mfd and terminals when diagnosing the hybrid pack. IIRC, it was 12.6 acc and 14.2 with a load. I had HOPED it WAS the 12v. It checked good at the time but yesterday was a little low at the terminals so I trickled it back up. Battery is almost exactly 7 years old and has given zero issues since installing. I suppose its possible she gave up the ghost in a few days but, my luck doesn't work that way.

    I am going to go in and test it on the mfd after work today and see what it says. It will have sat for close to 20 hours by that time. Other than that, that's all I have planned to do. I don't want to keep taking small swings on the new pack. I understand your tries can be limited and I don't want to go down that hole.

    Air, fuel and spark. I did clean the MFD and throttle body so, I'm confident with that. I had just filled up the previous day and the gauge is reading full bars so, pretty confident there. Spark, plugs might be next on the list to try.
     
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  14. ski.dive

    ski.dive Active Member

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    You should have had the dealer install it, it's not that much money to have the dealer do it. The dealer would have done the work correctly and you will have had a great extended warranty.
     
    #15 ski.dive, May 17, 2021
    Last edited: May 17, 2021
  15. Prodigyplace

    Prodigyplace Senior Member

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    I have not heard of anyone needing to claim the OEM Toyota warranty so that should not be an issue. Many people DIY with the newpriusbatteries kit of new cells for $1600 delivered anywhere in the US and then sell the good old module to lower the price further. @2k1Toaster has had no warranty claims due to failed cells either.
     
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