Problems with my Prius

I must first say that I have no knowledge of Gen1 Prius' but from past articles I've read here, I would first try an alternate power source for the 12v small battery before anything else. If it is/going bad, the hybrid battery may not be able to do it's job since the small 12v battery operates the electronics to let the big battery do it's job. Try hooking up another 12v battery via jumper cables just to see what happens. If everything returns to normal, replace the 12v battery. There are several articles here about how to test the 12v battery and even the hybrid battery. Good luck!

 

Yeah, sounds like a bad 12v battery.

 

Hi - this is Roy from Canada - will try to help you. I have 3 - 2001 prius cars that I have repaired the batteries. It sounds like you have run down the high voltage battery by trying to start it over and over again. If that is the case a warning will come on the dash that looks like a battery symbal. If you do not have this warning and the car will try to start the problem is with the gasoline engine. Have the mechanic clean the mass air flow sensor with sensor cleaner, change the plugs are two cheap things you can do.
You need a special meter that the dealer has to find out the condition of the high voltage battery.

Roy

 

Well, just to be clear, both batteries are in the trunk. The 12 volt battery (much like a normal car's in most respects) is behind the carpet near the left rear wheel, and the 274 volt battery (what your mechanic is calling the hybrid battery) is under the carpet behind the back seat.

At this stage of the problem, I don't think I've seen enough information to have any strong opinion on what is wrong with your car. Your mechanic seems to have a strong opinion, but I am not seeing enough information to justify it.

It would be helpful if you could post some more information, like voltage measurements at the 12 volt battery with the key off, then also with the key on (and maybe the headlights). That should be easy to do with tools that aren't hard to come by.

You also might be able to get a scan tool that can give you the trouble codes that are causing the exclamation point on the dash. Ordinary scan tools at auto shops won't do it (they'll talk to some of the computers in the car but don't know about others). A thing called a ScanGauge II will, though it is rather fiddly to set up. I see a lot of posts now where people are buying a "MiniVCI" device very cheaply from abroad and hooking it to a laptop. Toyota's Techstream software will run on that (and I think that's about $55 for a couple days of access, though I also see posts about people finding pirated copies, which I am of mixed feelings about).

The more information we have, the better conclusions we can draw.

-Chap

 

In your car the large high voltage ideally will be 278 volts DC. In reality it will be somewhere between 160 volts and 300 volts. This high voltage battery is used to turn the gas engine over to start the car, however the 12 volt small battery in the trunk is used to control a relay that brings the high voltage on to start the car. First make sure you have a well charged 12 volt battery - the small battery used in your car is very weak get a bigger battery and use jumper cables to power the 12 volt system. I am sure you have run the high voltage battery down and it needs a charge, this battery may be defective but can still be charged. The trick is to find someone to charge it or replace the battery. Check for a dealer that has such a charger, or you remove the battery and get another used one that is charged. If you cannot do this type of work yourself it becomes expensive and is not an easy fix. I have built my own charger that I use when my batteries get low this that may not be possible if you are not trained about electricity. I have removed and replaced the high voltage battery many times and can tell you how to do it but it can be dangerous. Hope this will help.

Roy from Canada

 

Just to be very clear, when I suggested posting some voltage measurements I was only talking about the twelve (12) volt battery near the left rear wheel well, which can be measured by anybody with a multimeter.

Your car is built so that there is nowhere you would have access with a conventional multimeter to measure the HV battery that way, until you get into pulling interlocks and removing safety covers, and it's built that way on purpose.

On the other hand, if you are able to get a reliable voltage on the 12 V side, you can turn the key on and use a ScanGauge II or other Prius-aware scantool to read the HV battery voltage from the car's computer. No muss, no fuss, no safety gloves, no danger warnings, and also you get not just the overall voltage of the battery but voltages for 19 separate subgroups of modules.

-Chap

 

trimel,
As a fellow Wisconsinite, I'd be happy to talk with you about your vehicle.

Call me and we can talk. 608-729-4082.

At minimum you may need a 12v battery, but you can unhook that and likely get it tested for free at an auto parts store.

But they could be correct, that you need a high voltage battery, and that will cost nearly $2,000 for a reliable replacement with a 3 year warranty.

 

There is a way for you to charge the HV Traction battery if it's run down without a lot of hassle. I can't say it's cheap; it's called a grid charger. I purchased mine from Raj at: Venice Hybrid Tech. The cost was about $285. I also purchased two harness, one for each of my 2002 Prii. I will be purchasing a 3rd harness for my 2005.

The wiring harness is connected to the HV Traction Battery as I've shown in the attached pictures and the harness is led out to the trunk area. I'm still trying to figure out a good way to mount it high up in the trunk where it's out of the way yet easily reached by the charger.

Did I need this? I wasn't sure. One of the Prii I've been working on has sat with an error for about 6 months. I've started it once in a while to see if it would clear the error (a P3009... ), so the battery charge never really flattened out. I felt I'd best be prepared to grid charge the battery and have the means to do it. It's always less expensive than taking it to a dealer. With three of these cars it's better to have than need than need and not have.

Oh, I did add the box (Harbor Freight Part Number: 69316 and the split loom wire covering from NAPA. I've suggested to Raj that these items be included with the charger. I like having the charger protected when not in use and the wiring harness be protected from being rubbed or crushed if it's in the luggage area. But for now, the charger is sold without these items.

 

Hi - this is Roy from Canada - the charger sounds like a good idea if t

 

The charger is a good solution if the battery is just run down, however being able to read the individual cell voltages is critical as he may have a problem with one cell in the battery and have to replace that cell. I had a similar problem that I found was a bad cell using my Mini VCI. I replaced the cell and the battery is still good after 6 months. I have been able to keep all 3 of my 2001 prius high voltage batteries in good condition using the Mini Vic and my charger so they are a good investment if you plan to keep the cars a long time. The Mini Vic is cheap (under $50) except you need an old XP computer to run it. The Mini Vic is very useful to clear codes and solve other problems.

 

Hi Roy, One question on the Mini Vic. You say it only runs on XP? Have you run it on a newer laptop running Win 7, or Win 8, using a Virtual Machine running Win XP?

If that would work, it would sure be more useful to those who don't have an ol' Win XP computer laying about. I just ordered the Mini Vic, since I've got an ol' laptop I can run it on. But, I'll also try it on a virtual machine and see if it works.

This will be fun.

 

I understand from other posts that you can use the mini vic with windows 7 , however I have never tried it on windows 7. If are successful a detailed method of the software used and any modifications would help.

Roy

 

Your car is 13 years old and 179,000 miles. If your hybrid battery is out, I would think a long time about sinking a lot of money in your car and consider junking it.

 

Mini VCI runs on Windows 7, 32 bit OS. There is a workaround that may allow it to run on Windows 7 64 bit OS but that did not work for me when I tried it. I am using that software on a MacBook Pro, with BootCamp and Windows 7, 32 bit OS layered on top.

If you have a Windows 7 or 8 Professional version and can run virtual Windows XP then there should be no problem running Mini VCI.