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

P3056 Error Code But Still Drives Fine

Discussion in 'Newbie Forum' started by Jbelsan, Jun 25, 2019.

  1. Jbelsan

    Jbelsan Junior Member

    Joined:
    Jun 25, 2019
    8
    2
    0
    Location:
    Wichita, KS
    Vehicle:
    2004 Prius
    Model:
    Base
    newb poster here. I've used this forum for research in the past, but never found a need to post. I've got a 2004 Toyota Prius with 256XXX miles that I bought when it had around 200K miles on it. Minor repairs in the 4 years I've owned it, but nothing crazy.

    Recently started firing a big red triangle, Check Engine light and Exclamation Point warning when driving at high speeds (60+). The codes pop on the dash, my cruise control and A/C turn off but otherwise there is no difference in driveability. When I turn the car off and back on, the A/C and Cruise work fine and again, the car runs and drives fine. The Exclamation Point code goes away on the first restart but the other codes stay on for 4-6 restarts and then turn off until they fire again.

    I got the codes checked at my local AutoZone and the only code they got was a P3056 (Battery Current Sensor Circuit Malfunction), which I can't find a ton about online in general, but maybe I'm not looking in the right place. I have seen the diagnostic specs, and I have a vehicle-savvy friend who thinks it would be worth replacing the Battery Current Sensor to start. I'm down to try - does this seem the right course of action or does a P3056 indicate bigger problems? This is my daily driver, so I'm still driving it to work daily with no issues other than the lights.

    Also, when I go to buy a Battery Current Sensor for my 2004 Prius online, I see 2- and 3-terminal versions - any way to tell which I need without taking the car apart?

    Thanks in advance!
     
    #1 Jbelsan, Jun 25, 2019
  2. Skibob

    Skibob Senior Member

    Joined:
    Sep 14, 2018
    2,912
    1,495
    0
    Location:
    Northern California
    Vehicle:
    2006 Prius
    Model:
    N/A
    You really need to know what the other codes are before you just go changing parts. Get a code reader that can read ALL the Toyota codes, not just the 1 the generic Autozone reader can read.
     
    #2 Skibob, Jun 25, 2019
  3. Jbelsan

    Jbelsan Junior Member

    Joined:
    Jun 25, 2019
    8
    2
    0
    Location:
    Wichita, KS
    Vehicle:
    2004 Prius
    Model:
    Base
    Thank you. Any recommendations on a good one that isn't overly expensive?
     
    #3 Jbelsan, Jun 25, 2019
  4. Skibob

    Skibob Senior Member

    Joined:
    Sep 14, 2018
    2,912
    1,495
    0
    Location:
    Northern California
    Vehicle:
    2006 Prius
    Model:
    N/A
    If you search the site you will find one or two that will work. If you have an older laptop or netbook you can get a mini VCI and techstream for very little money. You can even find and install an older version first to see if you can do it. The older version will still work.
     
    #4 Skibob, Jun 26, 2019
    Last edited: Jun 26, 2019
  5. JimboPalmer

    JimboPalmer Tsar of all the Rushers

    Joined:
    Apr 14, 2009
    12,470
    6,862
    2
    Location:
    Greenwood MS USA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    I am a random person on the internet, and should not be relied on!

    The most likely (to Me) is that the wires to the sensor or ECU have been damaged.

    Next likey is that the sensor failed

    Best Battery Current Sensor Parts for Cars, Trucks & SUVs

    Less likely is that the ECU has failed. (I see lots of owners deciding the ECUs have failed, I see no examples where that was the actual problem)

    And, as Skibob has mentioned, detailed sub-codes can pin these choices down.
     
    #5 JimboPalmer, Jun 26, 2019
  6. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,087
    5,804
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    The battery current sensor is for the HV battery and installed inside the HV battery pack under the electronics section cover. I believe it's the long negative cable that passes through the center of it. It's mounted using two torx screws.

    It's essentially just a current transformer. It has one plug that inserts into a socket on it's side. The other end of the wire plugs into the battery ecu. Gives a voltage signal to the ecu as to how much current is "discharging from" or "charging to" the HV battery.

    I don't think this is something you're just going to find at an Autozone or O'riellys Auto Parts.

    It wouldn't hurt to verify the wires are good, plus maybe even unplug it and replug it. It may be fine and just a crappy connection. If you do end up needing one, it is available, new, through Toyota, and I'm sure they're available on ebay, etc. Even I have some from disassembled batteries.

    https://www.toyotapartsdeal.com/oem/toyota~sensor~battery~current~g4283-47030.html?Make=Toyota&Model=Prius&Year=2007&Submodel=&Filter=()&Location=battery-battery-cable,,G4283
     
    #6 TMR-JWAP, Jun 26, 2019
    Last edited: Jun 26, 2019
    SFO likes this.
  7. Jbelsan

    Jbelsan Junior Member

    Joined:
    Jun 25, 2019
    8
    2
    0
    Location:
    Wichita, KS
    Vehicle:
    2004 Prius
    Model:
    Base
    I used an ODBII dongle and Dr. Prius to get the extended error codes. Here's what came back: Screenshot_20190627-194322.jpeg

    Posted via the PriusChat mobile app.
     
    #7 Jbelsan, Jun 27, 2019
(You must log in or sign up to post here.)