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P3030 2004 225K miles

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by mark010101, Jun 28, 2019.

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  1. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    P3030 has been thrown twice about 1 month apart. The car drives normally and the red triangle goes away when the system is restarted. Techstream says it is a disconnection between the battery and ECU. I am suspecting corrosion on the bus bars. All battery voltages and resistances are normal (see attached screen shots). My next steps are to pull the battery, and if corroded, clean the posts and replace the bus bars. I done some reading here and this sounds like the most likely issue. Thoughts anyone? Am I proceeding in the right direction? Many thanks.
     

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  2. Dxta

    Dxta Senior Member

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    Those resistance values are just too high.
    I think the threshold should be from 0.019-0.022 or so.
    Looking at your battery pack various temperature readings on all four locations, kinda like buttresses the fact that either the bus bars are corroded, or the pack is out of its way.
    Does the blower fan makes dome sort of noise at the rear seats?
    Opening up the pack, would revealed what the issue is.

    PS: you didn't state the mileage on her!
     
  3. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    Thank you for responding. The mileage is in the low 200s. The cooling fan runs occasionally especially on hot days.
     
  4. Dxta

    Dxta Senior Member

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    Opening up the pack would provide more info
     
  5. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    I will definitely open/examine the battery pack and report back with what I find. It will be several days since I am out of town.
     
  6. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    I have some more data. I looked at the freeze frame data when it threw the P3030 and the battery temps are are 32 deg F and the battery voltages are all 0.000 V. I now suspect the "disconnection between battery and ECU" is a loose ECU connector. I still will be pulling the battery tonight and looking for terminal corrosion which I also suspect since I am getting a live data internal resistance of 0.000 ohms for battery block 1. See attached screen shots for both the freeze frame and live data. Also according to the Toyota Shop Manual, normal battery internal resistances should range from 0.01 to 0.1 ohms and mine are at 0.024 to 0.025 (neglecting block 1).
     

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  7. TMR-JWAP

    TMR-JWAP Senior Member

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    At first glance, the photos you provided in post 1 show some really high temperature numbers. It looks to me like your car was probably sitting in the sun baking. Intake air is ~97, battery is ~120, and the fan is on speed 5 (max). If not in the sun, you probably should take a good look at the cooling fan to see if it's clogged. Although internal resistances are showing a bit high, they are all consistent with one another. I would be more concerned if there was an outlier showing a 34 or 35 or something. Internal resistance readings tend to climb as the battery warms up. If they stay high, but are consistent with one another, it could also just be showing it's age.

    looking at your second set of photos, yup. Definitely looks like a communication thing is going on. Verify all the HV battery plugs/sockets. Definitely inspect the plug and socket for the module voltage sensing harness where it plugs into the ecu.

    Your internal resistance values in the second set of photos look more in line with the norm for a mid-high mileage pack (other than #1)

    It will be interesting to hear what you find.
     
  8. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    Yes I noticed the high temps. I will check it again in the morning after it has cooled off. Even though the cooling fan mode was 5, it was not running. I used the TechStream software and tested the fan and it is fine. I ran it a bit to see if the battery temperatures would drop and they did not. So I might need to replace the bus (both sides) AND the temperature harness. I noticed that Electron Automotive sells a reconditioned bus set for $149 and a reconditioned temperature harness for $49. I read somewhere that these can also be bought from Toyota for around the same price but don't know the part numbers.
     
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    The wire harness with busbars and voltage sensor tabs is is called wire frame #2.


    8216547040 - Toyota Wire, frame, no.2 | Toyota Parts Overstock


    The other side busbars are easily cleaned and not really worth replacing, but if you really want to, they are also available.


    8267047070 - Toyota Block assy, junction. No.1; no.2 | Toyota Parts Overstock


    As for the temperature sensors, there's nothing wrong with yours. The values it shows make sense.
     
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  10. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    Thanks for the pointers to the parts. I pulled the cover on the battery tonight and both sides have a healthy amount of corrosion. See attached photos. I will order the parts, install and report back.
     

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  11. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    I have seen just one battery out of hundreds show 0.000 volts across all modules. After pulling it from a customs car I ran it for a few weeks in my own Prius before the problem came back. The malfunction caused the car to drive weird. The battery display stayed in the green. It seemed like the Prius just kept charging the battery because it thought it was empty. Replacing the battery ECU solved the problem.

    The temp sensors do not share a plug with the voltage sensors at the ECU. The common point for bad temp and voltage readings is not the connectors but the ECU itself.

    Has anyone ever noticed that Toyota call the computer inside the battery a CAB? That's Computer Assembly Battery.
     
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  12. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    I'm wondering about that too (battery ECU winking out). Can these be bought used? I see that are around $600 new. I am wondering if I am throwing good money after bad by replacing the buses and it would be better to get the new or rebuilt battery. A few years ago I bought a brand new battery from my local Toyota dealership for $2,200 at the beginning of 2016. If I could do that again, it would be something to seriously consider even though the car has over 200K miles.
     
  13. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    I checked the battery temps again this morning and they were at ambient (plus or minus 3 deg F). So temperature harness is fine. Will order wire frame #2 and see about cleaning up block junction assembly. I'll look around for a post about cleaning tips.
     
  14. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    Did that battery go in a different car?

    Battery ECU's are available at your local junk yards. Use Car-Part.com--Used Auto Parts Market to find them. Search for Computer Box Engine.
     
    #14 strawbrad, Jul 1, 2019
    Last edited: Jul 1, 2019
  15. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    Yes that battery went into my 2005 Prius. We have a 2004, 2005, and 2008. It is the 2004 that is giving me problems now.
     
  16. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    Swap the battery ECU in the 2004 with one of your other cars. Then wait to see which car codes.
     
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  17. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    On Sunday I installed the new front bus bar and cleaned up the back bus bar. Everything went smoothly and I have driven the car two days with incident. Below are two photos of the removed bus bar showing the oxidation.

    The new resistance values are lower (0.02 ohm vs. 0.03 ohm), but so were the battery temps at the time of new measurement (101.3 battery, 82.9 air intake). Does anyone know what is the upper operation range for the battery temps? The cooling fan is fine via the TechStream step test, but it seems it should be running at a higher speed to keep temps nearer the cabin temperature. I took two readings prior to the new bus install (max battery temps of 126 and 124). This seems high to me, but they were warm days (96.1 and 99.9 air intake respectively).
     

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  18. mark010101

    mark010101 Mark 04, 05, 08 Prius Owner

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    I meant to say above "with no incident". The car is still working fine and the P3030 error code has not returned. I feel confident that I can now reassemble the interior. It will be good to have a back seat again :)

    Mark
     
  19. TMR-JWAP

    TMR-JWAP Senior Member

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    That's great to hear!! (y)