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

Just bought a 2003 Gen 1: First Steps?

Discussion in 'Generation 1 Prius Discussion' started by evilroot, Aug 13, 2024 at 3:48 PM.

  1. evilroot

    evilroot New Member

    Joined:
    Tuesday
    3
    1
    0
    Location:
    Durham, NC
    Vehicle:
    2003 Prius
    Model:
    One
    I was driving a first gen Civic Hybrid (04, HCH1 I think) but the clutch went out. Actually intend to replace it myself, but that requires dropping the transmission (not a fun job with jack stands and hand tools). I was going to finance something newer, but this Prius was a good deal for $1,200 and I couldn't pass it up! Will fix the Civic later when I have access to a lift (have get to work, heh).

    Prius has 230k and shows a warning on the display but otherwise drives fine. From what I can gather the warning is a hybrid system general fault, guessing the modules are more than the magic .3V out of sync. Previous owner DID replace the traction battery once, but now showing signs of issues again and they didn't want to deal with it. Initially needed to be jumped, but after putting the 12V battery on charge overnight seems to start fine now. No issues with steering, and it drove a 20 mile trip without any complaint. The gas engine shuts off at stops like it should, and it does start out driving on electric for low speeds. It is possible the gas engine is kicking in earlier than usual but I don't really have a reference to judge by.

    From some browsing it seems the place to start is a bluetooth OBD scanner and the Dr Prius app to get an overview of the battery situation. I have done a quick check of what seem to be the most common problem areas (HV inverter coolant/pump, headlights, AC, etc) in addition to the normal used car stuff (alignment, tires, brakes, weird noises). Overall it was clearly VERY well taken care of.

    Looking at swapping the trans fluid and cleaning the pan/screen, any other suggestions for first orders of business? Is there a better diagnostic tool than the app that doesn't cost thousands (kind of defeats the point). I'm a professional electronics technician and have more better than average DIY capability!

    20240813_124047.jpg
     
    #1 evilroot, Aug 13, 2024 at 3:48 PM
  2. evilroot

    evilroot New Member

    Joined:
    Tuesday
    3
    1
    0
    Location:
    Durham, NC
    Vehicle:
    2003 Prius
    Model:
    One
    After a few days of driving and getting the Dr. Prius app I am starting to think the battery is okay for the most part. Showing around 307V, about 8V per module. Voltage difference of .17, resistances range from 19 to 22 milli-ohms. Nothing that jumps out at me.

    The code being thrown is P1437 which I'm looking up as evap. A vacuum leak on a 20+ year old car isn't exactly surprising.


    I have tomorrow off so I will start taking a bit of a deeper dive into things. Thinking I will do a general tune up (new plugs, clean intake manifold) along with the fluid swap, and see if I can track down the vacuum leak. Otherwise nothing seems particularly concerning. It is beginning to look like I will be under $1500 all said and done with the tags/registration/insurance and some new fluid.

    Also miss having a bluetooth head unit. Definitely on the to-do list.
     
    #2 evilroot, Aug 15, 2024 at 5:03 PM
  3. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    24,318
    15,828
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    You don't want to guess. "Hybrid system general fault" is a decent paraphrase, and there's a lot more to the hybrid system than just the battery; there are a couple hundred trouble codes for telling you what the actual issue is, and many have nothing to do with the battery at all.

    It often seems, maybe because the battery is the most obvious new thing people know is in a hybrid car, it comes to take center stage in people's minds at the expense of thinking of the car as an interoperating whole.

    You might consider getting some other app to use in diagnosing problems with the car, in addition to Dr. Prius, which is mostly known for its extra information screens geared toward trying to predict the battery life. Dr. Prius can also retrieve some trouble codes from the car, but not all of them, and when problems come up, a scan tool that can read all of them is usually the thing you want.

    P1 codes are manufacturer-defined. If there's some other car model out there where P1437 is an evap code, then that would be included in your web searches even though it's a bogus result for a Prius; that's the danger of doing web searches for manufacturer-defined codes. (Realistically, there probably isn't a car model out there that would use a P1 code for an evap issue, as many cars have evap systems and there are industry-standard P0 codes for evap issues.)

    In a gen 1 Prius, P1437 is about the vacuum-powered actuator for a valve in the exhaust system ahead of the catalytic converter. This thread may be of interest.

    P1437 would light the check-engine light, but I don't think it would light the hybrid warning. If you have the latter, then it is likely there are other trouble codes to be read that Dr. Prius did not show you. One of the other tools or apps that can show all of the codes in a Prius might be needed to get the whole story.

    If you have an old gen 1 Prius as a project, making sure you have your own scan tool that can read all the trouble codes will be a very good investment.
     
    #3 ChapmanF, Aug 15, 2024 at 6:11 PM
(You must log in or sign up to post here.)