HV control computer

It might be a good time to go to your local "AutoZone" parts dealer, and purchase a ScanGauge II device. $159 tool, of which you can program Xgauges into, where you can monitor several things about the Prius. A most valuable affordable tool, which you may find you'll leave installed in the car permanently.

Read through this thread regarding the tool, and the programming:

http://priuschat.com/forums/generation-1-prius-discussion/75468-03-classic-prius-scanguageii.html

I suspect the HV Battery, the ScanGuage II will help determine or rule that out. The mileage is in the range, of where the HV battery seems to start giving Gen1's issues, at least that is the case with the two Gen1's I've dealt with.

 

Once you manage to get the Prius started, what driveability symptoms exist other than the warning lights being on? For example:

- Does the gasoline engine run whenever you depress the accelerator pedal, no matter how gently?

- Do you find that the traction battery SOC gauge in the MFD jumps up and down more than normal?

- Do you find that mpg is worse than normal?

If you answer yes to those questions then I would agree that the traction battery itself probably needs to be replaced. Otherwise I would say that your dealer's diagnosis is reasonable, as:

DTC P3000, info code 123 is logged by the hybrid vehicle ECU and indicates an abnormal signal from the traction battery ECU.

DTC P3001 is logged by the traction battery ECU and indicates a problem with the traction battery ECU.

As a cost-reduction move, it would be possible for you to purchase a used traction battery ECU from a salvage vehicle for ~$200.
prius battery ecu items - Get great deals on Parts Accessories items on eBay Motors!

However, you would face the problem of how to install it. Since you say you have no expertise note that the installation requires opening up the traction battery case where you will be exposed to ~300VDC which constitutes a serious shock hazard. I recommend that you download repair manual pages at techinfo.toyota.com if you consider DIY to be a serious alternative.

You might ask your dealer whether they would be willing to install a salvage part if they are not held responsible for the outcome (in other words, you agree to pay for their labor time, probably 3 hours or so, regardless of whether the salvage part solves the problem). Or, see if you can find an independent mechanic who specializes in Toyota vehicles, who might be willing to learn how to do this job.

If you are serious about logging another 140K miles on the odometer, you will very likely face other problems along the way such as traction battery replacement, electric steering gear failure, etc. Hence it would be good for you to secure a repair source that will allow you to take advantage of salvage parts - unless you don't mind throwing $$$$ at every problem that will come up. Good luck.

 

Based on first symptom listed, I woud say that maybe low voltage - 12 V battery used for booting up the car computers is going bad.

So I would first check that one out. Then move towards more complex and potentially more expensive fault scenarios, like hybrid ECU and high voltage battery.

 

I suggest that you replace the 12V battery since it appears that the symptoms are worse in cold weather. After doing that, if you still have the no-start problem then it would be reasonable to accept the dealer's diagnosis that the traction battery ECU needs to be replaced.

 

Hi from a UK Newbie!
I had a period last year of some 5 months where the Hybrid lay outside without turning a wheel.
On attempting to use it again I found the 12V dead, the red car exclamation on the speedo lit, but did not check for codes.
On starting with my booster gel-battery pack, the warning remained until a period of 15-20 minutes of tickover charging and a key out restart, or after the first restart when driven for a few miles.
I replaced the 12Volt battery and the fault has not been repeated.
Hope this Helps.
Regards for the New Year from Scotland,UK.
Norrie.

 

These symptoms describe my experience this morning. Just purchased a used 03 Prius about 2 weeks ago. Not a single problem until this morning when the temperatures dropped below freezing. After getting it started, I drove to Autozone and their tester showed a DTC code of P3001.

DJG, how did you finally resolve it? Did the advice of purchasing a new 12v battery work?

Thanks.

 

I totally concur w/ replacing the 12v battery. My situation was very similiar to this (cold day, wouldn't start etc). I'd just about guarantee that will fix it.

 

I purchased a new 12v battery from the Toyota dealer and installed it. I tried starting the car, started right away, but then gave a warning screen and the car died after about 5 - 10 seconds. Repeated with the same story. Thinking the battery may be a little low from the dealer, I just finished fully charging it. I reconnected an the same symptoms. Starts, warning message, then dies after a few seconds. Thoughts? Do I need to reset anything after changing the battery?

Many thanks for any help,
Bruce

 

Hi Bruce,

You seem to have hit something that occasionally (not always) might happen when the 12 V battery has been disconnected. There's a whole thread about it; here's a post from where it happened to me.

For me it started right up again after clearing with a scantool. If you don't have one, you might try just unhooking/rehooking the 12 V battery again, or the other clear method involving jumper wires at the OBDII connector.

Hope this helps,
-Chap