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Prius wouldn't start

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by avoice217, Sep 29, 2022.

  1. ChapmanF

    ChapmanF Senior Member

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    The connector in your photo doesn't seem related to the current sensor, at least as far as I can tell from the 2006 wiring diagram I'm looking at. As for what that connector is, your fingers in the photo are in the way of seeing what wire colors go into it.
     
  2. avoice217

    avoice217 Member

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    Hey so I finally figured out where the connector goes. I did get it connected, but now the system is pulling up P0AFA. Gonna look into that one. I'm wondering if I should just reset the code since its a brand new battery in order to get the battery charged up.
     
  3. avoice217

    avoice217 Member

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    Hey guys, so there was a guy who uploaded a video on Youtube about his computer assy battery module that connected to the hybrid battery itself and showed a few burnt connectors, but based on mine, it still looks fine. So therefore im at a loss for ideas on what to look for.
     

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  4. ChapmanF

    ChapmanF Senior Member

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    So where is that, if I may ask? And what were the wire colors, if you can say without too much trouble?
     
  5. avoice217

    avoice217 Member

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    Not a problem, so it was the connector that goes to the battery current sensor. Apparently I couldn't find a video on Youtube that explained this, but I did see where the wire went into. When I went to my car, I immediately noticed the spot, but originally a wire nearby covered it & I didn't notice it at first. Now my current issue is P0AFA, which I'm guessing means that the ecu ecm is bad within the hybrid battery pack. There's no way its the wires since all the wires are brand new that came with the pack.
     
  6. Brian1954

    Brian1954 Active Member

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    If you look very closely, there is corrosion on some of the pins of the orange connector. I would replace the battery ECU with a used one.
     
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  7. ChapmanF

    ChapmanF Senior Member

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    Interesting ... the 2006 wiring diagram doesn't call out a connector there ... just looks as if the B13 connector that plugs into the battery ECU just has three wires from pins 14, 15, 16 directly to the current sensor. Also doesn't show their colors. I guess those were considered battery-internal construction details.
     
  8. dolj

    dolj Senior Member

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    Like Brian1954 I notice that the pins on the right side (in your photo) of the orange socket look a bit crusty, particularly on the bottom row.
    I don't know why people always assume the ECU must be bad. Likely your ECU is okay, it is just the pins in the orange socket that look funky. Maybe you can clean them up and make them nice and shiny or maybe you can just replace the ECU.
     
  9. avoice217

    avoice217 Member

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    Hey dolj, good catch on that. I didn't see that at first, but I am thankful that I took a photo of it. So are there any videos on how to clean the contacts or what exactly would you recommend? I mean if thats whats keeping the ecu from staying good, then I'll gladly work on that tomorrow.
     
  10. dolj

    dolj Senior Member

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    A picture is worth a thousand words:

     
  11. mr_guy_mann

    mr_guy_mann Senior Member

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  12. avoice217

    avoice217 Member

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    Hey all so even after cleaning up those contacts the best I could, the car is still giving me the P0AFA code. Any other ideas now?
     
  13. maleko

    maleko Member

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    Did you verify wire harness continuity from each nickel voltage sense tab to orange plug tip that connects to the battery ECU?
     
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  14. avoice217

    avoice217 Member

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    So are you saying that there's a chance that I may not have pushed in the wire harness to the orange part of the battery ecu?
     
  15. maleko

    maleko Member

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    In lieu of just starting to throw parts at it, if you want to get to the bottom of it, you need to start your troubleshooting by verifying the hardware (ie. wire harness) you have connecting the hybrid battery to the ECU is intact by checking each individual sense wire's continuity from its sense tab on the hybrid battery/bus bar attachment point to the tip of the orange plug using a multimeter (in continuity / resistance / diode mode, depending on your specific meter's settings).

    That will confirm whether or not there are any broken wires within the hardness bundle and whether or not it is even possible for the signal (ie. voltage) to make it from the hybrid battery bus bar stud terminal interface to the battery ECU in the first place.
     
    #55 maleko, Jun 28, 2024 at 3:53 PM
    Last edited: Jun 28, 2024 at 7:25 PM
  16. ChapmanF

    ChapmanF Senior Member

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    Each of the wires you see at that orange connector has a far end too, at a terminal that sits under the nut at one of the module studs. And each one of those wires has to conduct all the way from that terminal to the corresponding ECU pin.

    P0AFA is a code that is only set when at least one of those voltage readings is totally bogus, say two volts or less. There's no way two volts is a realistic voltage reading for a 6-cell NiMH module, even a really tired one at deep discharge, so this is not a code about any battery module being tired or undercharged; it's really saying specifically that the reading from at least one is plainly bogus, as you might see when one of those terminals or wires gets broken or left unconnected, or an ECU pin is kaput.
     
  17. mr_guy_mann

    mr_guy_mann Senior Member

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    I would look at battery block voltage data from the battery ecu. Whichever one looks "wrong" will point you toward the problem circuit.

    Posted via the PriusChat mobile app.
     
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  18. avoice217

    avoice217 Member

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    So I can check all the connectors going to the battery pack & going from there, that's not an issue. I guess my question is how can I possibly test to see if the ecu itself it at fault? I've tried doing research and apparently there's nothing about testing those in itself. The closest I've come is that someone in Cali has refurbished them, but that's about it. I'm guessing there's something that's on a board inside of the module itself that's possibly gone. Unfortunately brand new modules themselves can only be found through a dealership & even then its 10x what a used one is worth.
     
  19. avoice217

    avoice217 Member

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    Ok so another small update on my end; so I took the ecu out and for some weird reason my headlamp that I used to pull the ecu out was able to help me detect corrosion on one of the contacts (bottom right side if the flap is facing down) and so I took it out and was able to do some cleaning (only the top part of the contact). However, due to limited supplies, I'm not able to get the front part of the contact nor the sides of the contact. I was able to use a nail file to remove the corrosion from the top, but I honestly have no idea of what I can use to get the front as well as the sides to get rid of the corrosion. If anything, I'm hoping that this will resolve the issue once I can get rid of the remainder of this corrosion.
     
  20. ozmatt

    ozmatt Active Member

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    The joys of 20 year old cars with 50 year old battery technology!

    I use a tiny piece of 2500 wet&dry paper with a touch of white vinegar wrapped around a tiny screwdriver and slowly but patiently work my way around the effected pins (inside the ecu too, not just on the outside) then after I'm finished cleaning I go back over it with a mixture of baking soda and warm water to neutralize the acidity of the vinegar then finally finish off with isopropyl alcohol to get everything clean, if you dont clean it all 100% thoroughly it will grow back exponentially

    Also If the ecu has nasty pins the wire harness or at least effected wires will be bad too (unless this is a new pack, of course) in that case get the ecu 100% spotless or your inviting corrosion over to the new wire harness from the ecu pins!

    I have recently learned to de-pin and swap out bad individual wires from the harness, it's a headache but makes me feel better about the "fix" if all effected wires have been replaced at the same time I clean the ecu

    People tend to advise against using any sort of spray or dielectric grease on these parts but in wet areas and cars that leak I now use corrosion inhibitor spray on the bus bars and sensing wire harness plug/ecu to help combat this problem reoccurring too soon..

    When your all finished and zipped up it's important to keep the car cabin dry and free of humidity or the green fuzz will be back real fast



    Posted via the PriusChat mobile app.