1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Need help diagnosing P0AFC

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by SB6, Dec 3, 2022.

  1. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Never mind, I managed to figure it out using some breadboard jumper wires I had. Here are my results:

    1. CHECK HARNESS AND CONNECTOR (IGCT VOLTAGE)
      1. 11.92V between c1-4 (IGCT) and c1-8 (ground) with IG on and c1 connected. This is within the 11V - 14V range given in the manual. The repair manual says if this test OK, then to replace the battery smart unit. Does that sound correct, or is this another mistake in the manual? It says if the test comes out not good (NG?), then to continue to the next step. Should it be the opposite?
    2. CHECK FUSE (IGCT, IGCT NO. 2)
      1. Both fuses showed continuity. Repair manual says if this tests okay, then to proceed to step 3.
    3. CK RELAY (IGCT)
      1. As mentioned in Post #13, this test came out okay. I get 0L (infinite resistance/no connection) when I measure across 3 and 5 without 12V applied across pins 1 and 2. I get continuity/0 Ohms between pins 3 and 5 if I apply 12V across pins 1 and 2. Additionally, with no voltage applied, I measured about 170 Ohms across 1 and 2. This is the opposite of what the repair manual says, but we established that the repair manual may be incorrect here. The repair manual says to replace the relay id this tests NG, or to continue to step 4 if this step tests okay.
    4. CHECK HARNESS AND CONNECTOR (IGCT RELAY - BATTERY SMART UNIT)
      1. I measured and found continuity between c1-4 (IGCT) and the IGCT relay terminal 5 on the fuse block. This is with c1 disconnected form the battery smart unit, and power on IG. The repair manual says that if this tests OK, then to check and repair the power source circuit.
    For anyone else reading this, this is all of course with the service plug grip disconnected.

    I guess my next step is to check the power source circuit, per test results from step 4. Or did step 1 already narrow it down to the battery smart unit? Anyone have any guidance here?
     
  2. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Managed to get the battery smart Unit out, and saw what looked like 2 discolored pins (11 and 12?) on the orange connector. Opened it up, and it looks like pins 1, 2, 3, 11, 12, 13, and maybe 4, 5, 6, 14, 15, 16 are blackened. Flipped the board over, and it looks like pins 12 and 13 are burnt. See imgur pictures below.

    I'm guessing I need to dig further into the battery to see if the pins were burnt because of an issue with the cells, rather than the issue just being the battery smart unit?



    Code:
    https://imgur.com/gallery/J4hiK5C
     
  3. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,545
    15,250
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    That's not an uncommon problem. It just happens, going back to Gen 1.

    Along with the smart unit, you'll probably want to replace the set of busbars with skinny sense wires attached, going along one side of the battery. In previous generations, you could buy that separately from Toyota as the "number two frame wire", and it didn't cost much.

    Here's the bad news for Gen 3: they won't sell you a number two frame wire any more. Toyota's new story is "just replace the battery." Yay.

    But maybe you can get a decent number two frame wire from somebody who does a lot of work on Gen 3 cars.
     
  4. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Is there not a part number at all for the 3rd gen No. 2 frame wire? I see a few on eBay that look to be for 1st or 2nd Gen, but I'm guessing those wouldn't fit a 3rd gen.
     
  5. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Also, is there any reason a battery smart unit numbered 89892-47080 would not work on my 2010 Prius II?
     
  6. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,545
    15,250
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    No part number, just "NO3 This part is not supplied as an individual part, because it is difficult to keep the function / quality of the part assembled."

    [​IMG]
     
  7. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Is it the one directly under the part labeled G9282?

    Do you happen to have a picture of the actual part? I'm in contact with an eBay seller right now, trying to see if they have the wire. They're asking for a picture. Haven't managed to open up my battery yet, so I don't have a picture myself...
     
  8. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,545
    15,250
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    It's the one along the left edge of the module stack, held on by 28 of the G9291-47011 nuts.

    The little pigtail on the far end is what plugs into the smart unit.

    I could perfectly well "keep the function / quality of the part assembled" if they'd sell me the ding-binged part.
     
  9. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Turns out the seller does have the wire harness. I'm debating whether I should buy it, or if mine may be fine.

    I was able to open up the battery cover, and there's quite a bit of build up on the blade nuts. Wasn't able to see yet if there's any burn marks on the terminals on the seat-side. I'm doing this with the battery still in the car, so that side is a bit difficult. Now that I've verified there's buildup on the terminals, though, I guess I should take the battery out and clean it anyway... I just was hoping I wouldn't have to put too much time into this, as I'm supposed to be traveling soon (thankfully not necessarily in this car)
     
  10. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,545
    15,250
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    The terminal nuts can show corrosion, and also the visible areas of the busbars not beneath the nuts, without affecting the contact between the terminals, busbars, and nuts. When properly torqued, typically those contact areas are compressed to the point of being gastight, and you find them clean and shiny when (if) you disturb them by taking the nuts off.

    But the terminals in the number 2 frame wire connector that plugs into the smart unit probably look pretty much like the terminals in the smart unit where it plugged in.
     
  11. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Replacement smart unit finally came in. However, the board looks a little different from my old one. Can anyone tell me if they think the new one would be compatible with my 2010 Prius II?


    Code:
    https://imgur.com/gallery/kVqFLnQ
    Top (part #89892-47080/175100-7280, board #175131-7280) is new.

    Bottom (part #89892-47020/175100-7171, board #175131-7170) is old.

    By the way, for anyone looking to open up the unit to access the board, I found a #2 Phillips/PH2 bit screwdriver to be perfect
     
    #31 SB6, Jan 11, 2023
    Last edited: Jan 11, 2023
  12. ASRDogman

    ASRDogman Senior Member

    Joined:
    May 29, 2018
    5,982
    3,207
    0
    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    No picture, site doesn't work..

     
  13. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Code:
    https://imgur.io/gallery/kVqFLnQ
    If you use the link, does it work? I'm not sure why, but my adblocker blocks imgur pictures embedded here. But if I open the link, it works fine
     
  14. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Any thoughts?
     
  15. Mendel Leisk

    Mendel Leisk Luddite

    Joined:
    Oct 17, 2010
    55,075
    38,455
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Where do your pics originate? There’s got to be an easier way to post them. Imgur’s modus operandi seems purely designed to make itself indispensable and thwart users.
     
    #35 Mendel Leisk, Jan 14, 2023
    Last edited: Jan 14, 2023
  16. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    I think I just figured out how to post the pictures directly here. But did the imgur link not show up in post #33? Or it doesn't work?

    Anyway in the first picture attached here, top (part #89892-47080/175100-7280, board #175131-7280) is new. Bottom (part #89892-47020/175100-7171, board #175131-7170) is old.
     

    Attached Files:

    Mendel Leisk likes this.
  17. Mendel Leisk

    Mendel Leisk Luddite

    Joined:
    Oct 17, 2010
    55,075
    38,455
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Didn't work, on iphone or win10 pc, for me. Yeah, if you're posting via a computer or phone, just use "upload a file" button. Then you can either attach, or embed in the text. If your image is in "clipboard" (the on-deck thing to be copied), you can simply "paste" the image wherever you want, in the text.
     
    CR94 likes this.
  18. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Yeah, I posted above.


    I was hoping to install the new sensor and voltage sense wires this weekend, but I tried to remove the old sense wires, and at least one of the nuts seems to be rounded... Any suggestions on a quick replacement, I can get this done this weekend? I'll have to figure out how to remove it first, though. Conversely, if I get it off, I'll need a replacement ready
     
  19. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Fortunately, I was able to borrow a friend's extractor set and get out the damaged nut. But I need to find a replacement soon. Any suggestions?

    I did see in another thread that the nuts are supposed to be M5 x 0.8. But I'm not sure where I can find a washer style nut in that size near me...
     
  20. SB6

    SB6 Member

    Joined:
    Jan 27, 2019
    314
    69
    0
    Location:
    Texas
    Vehicle:
    2010 Prius
    Model:
    II
    Could not find anything nearby, so I ordered a pack of these... Seems like some random Chinese seller, but it is supposed to be the fastest delivery (tomorrow). Hopefully I didn't screw myself over, and they turn out to be decent quality, but I don't know.


    Code:
    https://www.amazon.com/Yadaland-Stainless-Fastener-Multi-Function-Furniture/dp/B08TM4DJ6P/
    I don't know why I didn't think of it yesterday, but I could have checked with the dealership parts department. Unfortunately, they're closed on Sundays