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

P0A9B Hybrid Battery Temperature Sensor Cicuit

Discussion in 'Gen 2 Prius Technical Discussion' started by 3prongpaul, Dec 6, 2010.

  1. 3prongpaul

    3prongpaul Hybrid Shop Owner, worked on 100's of Prius's

    Joined:
    Jul 18, 2010
    954
    720
    1
    Location:
    Boulder Hybids, Boulder, CO
    Vehicle:
    2006 Prius
    Model:
    N/A
    Had a customer car with DTC P0A9B in 2005 Prius with 170k miles so out of warranty.

    Car would code immediately when turned on but would drive fine, 45MPG average etc.

    Dealer had told customer solution is to "replace entire HV battery assembly". .

    Customer battery ECU was 89890-47070.
    Got a slightly newer battery ECU 89890-47071 from a hybrid recycler in Denver. Replaced only the battery ECU, cleared codes, no more problems. Car now running great.

    Thanks to Eric at Adopt-A-Part for hooking me up with a good used battery ECU at a fair price.

    .
     
    theforceprius and dogfriend like this.
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,200
    6,474
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Nice work. If there were no driveability issues that provides a good clue that the traction battery is indeed OK.
     
  3. budrow56

    budrow56 Junior Member

    Joined:
    Jun 13, 2014
    45
    1
    0
    Your traction battery has a warranty life of 100000 miles in most states and 150k in California. And their are lots of tech centers selling refurbished batteries. And a guy in Tampa sells this charger to equailie the cell
     
  4. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    108,875
    49,469
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    but the o/p said the car had 170k, and the battery was fine.
     
  5. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,651
    3,862
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    Another resurrected thread, almost at 4th birthday. LOL.
     
  6. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

    Joined:
    Sep 10, 2012
    1,417
    510
    0
    Location:
    Harrison Township, Michigan
    Vehicle:
    2015 Prius
    Model:
    Four
  7. Bachelor boB

    Bachelor boB Junior Member

    Joined:
    Jul 12, 2022
    19
    1
    0
    Location:
    Chicago
    Vehicle:
    2007 Prius
    Model:
    N/A
    Does this imply that that module does not need to be VIN flashed? That it can simply be replaced?
     
  8. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,995
    15,589
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    There are around a dozen-plus different ECUs in a gen 2 Prius—more like a couple dozen in later gens—and only a few of them care at all about the VIN or what car they're installed in. By and large they're just plug and go.
     
  9. Bachelor boB

    Bachelor boB Junior Member

    Joined:
    Jul 12, 2022
    19
    1
    0
    Location:
    Chicago
    Vehicle:
    2007 Prius
    Model:
    N/A
    So what ECUs *do* care about the VIN and therefore need flashing? I am having massive problems and intend to replace the HV Control ECU (part# 89981-47211 / 89981-47212), the Engine Control ECU (part# 89661-47160 / 89661-47161 / 89661-47162), and the Computer Assy, Battery / Computer Assy, Soc (part# 89890-47071 / 89890-47073).
     
  10. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    7,967
    4,711
    7
    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    The engine control ecm will need a vin flashed and you will likely need the immobilizer ecu reset and configured for your keys. Some online sellers will do the vin and update firmware as part of the deal.

    If this is a result of a reverse polarity jump, the odds are good the ecus are still good but some fuses were missed or the orange hv disconnect was not snapped in after it was closed.
     
  11. mr_guy_mann

    mr_guy_mann Senior Member

    Joined:
    Sep 3, 2020
    3,465
    1,505
    0
    Location:
    NJ-USA
    Vehicle:
    2006 Prius
    Model:
    Four
    <shrug>

    I've plugged in a used ECM on my 2006 and the VIN (as reported by a scantool) didn't change. Didn't have to do anything with security or resets.

    The service manual indicates that a handshake procedure is required if you replace the hybrid control ecu.

    Posted via the PriusChat mobile app.
     
  12. mr_guy_mann

    mr_guy_mann Senior Member

    Joined:
    Sep 3, 2020
    3,465
    1,505
    0
    Location:
    NJ-USA
    Vehicle:
    2006 Prius
    Model:
    Four
    What kind of problems? What codes do you get? What systems can communicate with your scantool?

    Posted via the PriusChat mobile app.
     
  13. Bachelor boB

    Bachelor boB Junior Member

    Joined:
    Jul 12, 2022
    19
    1
    0
    Location:
    Chicago
    Vehicle:
    2007 Prius
    Model:
    N/A
    After a catastrophic IC engine failure, our 2007 Gen2 sat for 2 months until I replaced the engine. The hybrid battery is now going nuts, quickly changing from 1-2 red bars to suddenly the max green bars, then 1-2 red bars, quickly climbing and descending through the blue bars. Every start throws multiple dash warnings, including the Red Triangle of Death. Cheap ODB scanner plugged in for repeated clearing of codes.

    Worst part is, when it throws codes, it often also revs the engine to the max RPM and stays there. I have to pull over ASAP, clear the codes, shut the car off, turn the car on, clear the codes again, then resume. So, something is obviously causing a misreading of the throttle position.

    I'm attaching TechStream screenshots of the pages showing readings where error codes are. One or both of the cells in the hybrid battery blocks #4 and #12 clearly need replacing. No problem with that, as I've replaced bad cells twice before.

    My question is, should I be replacing any ECU? I have a replacement Engine Control (original is part# 89661-47160; salvage is part# 89661-47161). Once the hybrid battery is out and disassembled, does anything in these screenshots indicate that I should also replace the Computer Assy, Battery (assuming original is part# 89890-47071; salvage could be part# 89890-47072 or 89890-47073) and/or the HV Control (assuming original is part# 89981-47211; salvage could be part# 89981-47212)?

    Also, does the 'Engine and ECT' status being "Inc" mean that that module is dead = no communication with TechStream at all?


    Screen Shot 2024-06-25 at 11.19.29.png

    Screen Shot 2024-06-25 at 11.18.02.png

    Screen Shot 2024-06-25 at 11.18.52.png
     
  14. Bachelor boB

    Bachelor boB Junior Member

    Joined:
    Jul 12, 2022
    19
    1
    0
    Location:
    Chicago
    Vehicle:
    2007 Prius
    Model:
    N/A
    Can that be done with the 30-minute jumper between the ODB port pins #4 and #13 trick?
     
  15. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,995
    15,589
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    What RPM? Can you use your scan tool to read the RPM at that time? I've seen posters exaggerate and say something sounded like max RPM when it wasn't really close. I think max on a gen 2 is around 5000.

    Is it really "obvious" that's the reason the car has increased the engine RPM? Or would it be more accurate to say an increase in engine RPM is observed, and the reason hasn't been pinned down?

    I've read on RC forums that the NiMH chemistry is exothermic when charging, endothermic when discharging. If the battery has been measured as hot, one way the car can cool it is by using power from it (at a moderate rate; too much, and resistive heating would outweigh the chemical cooling). The car can do that by using some battery power to twirl the engine at a higher RPM.

    If this is a protective move in response to sensed battery temperature, there might be little benefit in going to such lengths to thwart it.
     
  16. Bachelor boB

    Bachelor boB Junior Member

    Joined:
    Jul 12, 2022
    19
    1
    0
    Location:
    Chicago
    Vehicle:
    2007 Prius
    Model:
    N/A
    When the car is traveling at any give velocity, you suddenly get the Red Triangle of Death, the weird circle with 2nd arcs on both sides and ! in middle, and the Engine Maint light, and the engine jumps to a *much* higher RPM, and stays at the *much* higher RPMs, through braking to a stop, and stays at the *much* higher RPMs until you shut the car off, then… yes, some module is misreading the throttle position and deciding that the throttle is being floored. And I mean floored!
     
    #16 Bachelor boB, Jun 26, 2024
    Last edited: Jun 26, 2024
  17. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,995
    15,589
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    I take it when you say 'throttle' here you mean the accelerator pedal. People often loosely call both the 'throttle' (as, in other cars, one is usually connected to the other) but in the Prius it pays to be specific, because the throttle (on the engine) and the pedal (in the cabin) both have their own position sensors that have to be read by modules. (Different modules—the throttle position sensor is wired to the engine control module, while the pedal position sensor is wired to the HV control ECU).

    Your conclusion that the HV control ECU is misreading the pedal position as floored is easy to test. Connect a scan tool while this is happening, pull up the HV control ECU live data list, and report the readings ACCEL POS #1 and #2.

    (The accelerator pedal in fact contains two independent position sensors, which is why there's a reading #1 and #2. If the module ever sees the readings not in sync the way they should be, it knows there's an error and enters a limp-home mode.)

    While connected, the same scan tool can be used to get the trouble code(s) to identify what issue(s) the car has detected. The live data list can also show what the engine RPM is, so "*much* higher" can be pinned down better.
     
  18. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,651
    3,862
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    No, not based on any of the data you have posted so far.
    Nope. The only reason to replace the battery ECU would be if any of the pins in the orange socket on the ECU were corroded. If you found that, you would replace the battery ECU and the voltage sense harness (call the No. 2 frame wire) to ensure a long-term reliable fix.
    Nope. Inc is an abbreviation for incomplete. The ECM has not has enough time or drive cycle conditions to complete all of its monitors.
    Nope, that is not necessarily the correct conclusion. ChapmanF had a possible explanation.

    You haven't touched on the two codes that would be the ones I would be focused on and that is the P0A80 and the P3022. Clearly, the battery is not happy. In addition there really should be a P3014 because block 14 is not happy either.

    You have at least 2 modules to replace and then a reconditioning of the pack, if that is the way you want to go but it is a lot of work for maybe 2 years of extended life. For me, if I was in this position, it would be a shiny new pack from Toyota then be done with it for the next 12-17 years.
     
    #18 dolj, Jun 26, 2024
    Last edited: Jun 26, 2024
    mr_guy_mann and Brian1954 like this.
  19. Brian1954

    Brian1954 Active Member

    Joined:
    Jan 31, 2021
    812
    303
    0
    Location:
    South Central PA, USA
    Vehicle:
    2011 Prius
    Model:
    III
    ^^ agree 100% with dolj
     
  20. Brian1954

    Brian1954 Active Member

    Joined:
    Jan 31, 2021
    812
    303
    0
    Location:
    South Central PA, USA
    Vehicle:
    2011 Prius
    Model:
    III
    Please tell us about the battery module replacements that you previously did. When did you do the first replacement, and how long after the first replacement did you do the second replacement? How long has it been since the second replacement?