'02 Prius, Not starting, P3125 Code

You're going to need a Prius Aware scanner such as a MiniVic or an Xguage II to recover the sub-coded and further pinpoint the problem. Lots of the member here buy the MiniVic (which comes with the Toyota Tech Stream Software), it's attached to a Windows laptop (preferably WinXP).

 

Yes, the Toyota software does come with the MiniVic... it's on a small CD included with the MiniVic.

 

Sort of. You can actually download the software at no cost from a number of places -- usually a dropbox that some helpful person has posted a link to on a Toyota forum. And the cable, as I assume you know is more than just a standard USB.

All you really need is the cable. If the software comes with it, fine. Otherwise, as I said, you can find it across the web.

 

I think the versions are up into the 9.XXX now, but for my car, I just used the one linked here....which is a 7.XXX
I will put the link in the next post, since I am just one post shy of being able to post links...

 

Link promised:
TechStream software and cable for $35 - Page 2 - TundraTalk.net - Toyota Tundra Discussion Forum

 

It's been awhile since I installed it, but lots of helpful instructions floating around. But IIRC, the thing that bedeviled me was that BEFORE you install the Techstream driver, make sure the USB cord is plugged into your computer. Don't plug it into the car or anything...maybe your computer knowhow is way beyond mine and that's a "duh" for you, but for me.....

I did not do this and it took me a couple of hours of troubleshooting to figure out the problem.

 

I've had a few 3125 codes in a few priuses and they were both a bad stator coil. Such as:

 

Once you have the sub code I have a manual that describes what the sub code means and I may be able to send it to you in pdf form. The manual is a service manual(pdf) and may help you with other problems in the future. My e-mail is ([email protected] ), I have not tried to send a pdf file and may need help with the procedure. I own three 2001 prius that I have repaired for various problems over the last year. I personally have not encountered the 3025 code so can not give you advise at this time.
The high voltage battery charges the 12 v battery through a dc to dc converter, the stuck key could kill both the 12v and hv battery. If you can get the car to start let it charge up the high voltage battery (before that charge your 12 volt battery from a separate charger), reset the code and see if it comes back. When the 12v and high voltage batteries are low many strange codes come up so do not put too much faith in them until both batteries are in a well charged condition. Best of luck.

Roy from Canada

 

When you were driving the car did you notice a very slight higher pitched winding sound when the car is decelerating? Like this example:

Is your inverter coolant pump working? thats a very common gen 1 Prius problem. Inverter coolant Pumps are known failures. if it's not working you can fry the inverter causing p3125. If pumps good then your inverter is probably good and problems in the transaxle. Another known gen 1 Prius problem is an o ring that wasn't set correctly at the factory causing the transaxle to not be adequately lubricated. Frying transaxle and burning out stator etc. causing p3125. you should drain transmission fluid and look at it closely for metal particles. Let us know how you make out?

Ps.No worries because you can buy a salvage transmission for $250 or so and can be put in for 400-500. Good luck!

 

problem started with the gasoline engine quitting on you so you should look towards that as your primary problem. When you drove on battery (after the gas engine stopped) you took the battery to a very low voltage so it would not turn over the gasoline engine to restart it. To help I need to know the following:

Does the gasoline engine start - you may think it does but the sound the car makes when starting sounds as if it is running - all you are really doing is running down the battery. Use the mini vic to see the percent charge on the battery. You must get back to us with the condition the car is in right now - is it running or not?

 

Yes, C1259 is sort of a distraction code most of the time. It's a code from the ABS computer, and it gets stored any time the ABS computer got a message from the HV computer saying anything at all was wrong on the HV side. So you end up fixing whatever the HV ECU was griping about in the first place, and then the C1259 can be cleared in the brake ECU and won't come back.

-Chap

 

I am going to assume the car is in the same condition you stated in your first post in that you cannot get the gasoline engine to run continuously.

If your inverter was gone you would not have been able to drive 2 miles on battery as it is the device that converts the hv battery voltage to a 3 phase AC voltage which was used to drive you 2 miles. You are an electronic person look up inverter - all it does is takes DC and inverts it to AC. MG1 and MG2 are motor generators. In the motor mode they drive the front wheels in the generator mode they generate ac voltage to the converter/inverter electronics box to charge the hv battery. I am trying to explain in simple terms (it is more complex then that in reality) . Car mechanics have a hard time troubleshooting the gasoline engine because they usually kill the HV battery by multiple starts. You know how the gasoline engine works- either fuel or spark is usually the problem to cause the car to stop - when that occurs on the prius you can still drive it a short way electrically (as you did) indicating to me that the inverter and MG system may be OK. Get the gasoline engine going by checking fuel and spark, when that runs then consider problems with the inverter. Hope this helps.


You may want to consider getting a high voltage charger that will allow you to charge the hv battery if you run it completely down, check other posts on this site on where to buy. The dealers do not usually have a charger in the shop to do this

 

You are not thinking about this properly. When your gas engine is running it will generate 550v 3 phase AC (through one of the motor generators) that is then fed to the converter(located in the inverter casing) that converts it to DC voltage that then charges the high voltage battery. If you can not get the gas engine running you can not generate a voltage to charge the battery. The inverter is not stopping the gasoline engine from starting up and running. You must get the problem with the gas engine solved so it will charge the hv battery and provide power to drive your vechicle. The gas engine does not directly drive the wheels as in normal cars, it drives a generator that creates a 3 phase 550 v AC voltage that in turn drives a 3 phase AC motor (MG)that drives the wheels. The hv battery provides power to the inverter that inverts it to 550v ac that drives the wheels as well. Regenerative braking is created by braking or the inertia of the vechicle while slowing down that creates a voltage in the generators (MG1 and 2) that in turn create a voltage to the inverter /converter that charges the battery. I repeat get the gas engine running.
Towing the car with the front wheels down will create a voltage that could harm your electrical system, should tow with front wheels off ground do not try to get it running by towing.