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

2002 Prius, P3191, ECM replacement reccomended

Discussion in 'Generation 1 Prius Discussion' started by Bob5386, Mar 5, 2018.

Tags:
  1. Bob5386

    Bob5386 New Member

    Joined:
    Mar 5, 2018
    1
    0
    0
    Location:
    Michigan
    Vehicle:
    2002 Prius
    Model:
    I
    I have a 2002 Prius with over 300k miles, and I recently got the triangle of death right after filling up my tank a few weeks ago. I've driving on it since I only commute a few miles a day, and I assumed the HV battery was on its last leg so I was going to run it into the ground. I recently took it on the highway and it appears that the HV battery completely shut off while I was slowing down to exit.

    The energy tab showed that there was no power going to or from the battery, and the car sounded like it was essentially in neutral when accelerating, and made a sort of whirling noise when I let off the acceleratory (sort of like a vacuum after you turn it off).

    I pulled over, kept the car on, and then tried accelerating again and it appeared the battery kicked back on.

    It's still acting weird, it seems the HV battery is discharging and charging very quickly, the car is very loud when accelerating and my MPG has dropped from around 38 to 20. When I idle, the engine kicks on and off every 5 seconds or so. Again, I'm assuming the battery is on its last leg.

    I took it to AutoZone to read the codes and the guy who read them actually used to work for Toyota. He's saying all I need is an ECM replacement but it definitely seems like an HV battery issue to me, but I admittedly don't know what I'm talking about.

    Here are codes:
    P3191
    P0420
    P0440
    P0440 (again)
    P0441

    I know there's also something wrong with my gas sensor, since the triangle popped up after filling up and the dash meter is always wrong. Also, the check engine light is pretty much constantly on, but I'm not too concerned about that.

    Anyways, is there any way that this isn't my HV battery and I just need a new ECM?
     
    #1 Bob5386, Mar 5, 2018
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,440
    15,189
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Hi ,

    The codes you've listed are all from the ECM (a/k/a the engine ECU). There are no codes in your list related to the battery, or anything else in the car. On the other hand, the car's behavior suggests there could also be codes detected by the HV ECU or by the Battery ECU, and the Autozone guy may have simply used a code reader that only can see the engine ECU, and isn't telling you any of the rest of the story.

    Do you have any lights on the dash besides the yellow Check Engine?

    I would suggest using Techstream to scan for trouble codes, as it can show codes from all of the ECUs in the car. It can also show you real-time data such as the internal voltages across the battery, which can give you some more information if the battery is a bit out of balance but not enough to set codes yet.

    -Chap
     
    #2 ChapmanF, Mar 5, 2018
    Brian in Tucson likes this.
  3. Brian in Tucson

    Brian in Tucson Active Member

    Joined:
    Oct 15, 2016
    981
    453
    0
    Location:
    Tucson AZ
    Vehicle:
    2003 Prius
    Model:
    N/A
    Chap is right, the generic scanners at Autozone, etc. can't do a proper scan of the Prius' ECU. It takes software that's developed for Toyota vehicles. I would suggest that you get it to a hybrid shop, tho not necessarily a dealer. Techstream pirated software and a mini VCI cable are available online, Amazon, among others, sell them. Quality can be spotty, you pay yer money and take your chances.
     
    #3 Brian in Tucson, Mar 5, 2018
  4. Brian in Tucson

    Brian in Tucson Active Member

    Joined:
    Oct 15, 2016
    981
    453
    0
    Location:
    Tucson AZ
    Vehicle:
    2003 Prius
    Model:
    N/A
    Btw, at 300,000 miles, your Prius itself may be circling the drain. Sorry.
     
    #4 Brian in Tucson, Mar 5, 2018
(You must log in or sign up to post here.)