2001 prius electric issue (battery)

Hi Tony, welcome to PriusChat! Three cheers for taking on a project Prius. You've got the right attitude, viewing it as a learning experience.

One first stop you'll do well to make is techinfo.toyota.com. You can subscribe there and view all the service manual info for the car. Since the hybrid design of the Prius is new to you, I strongly recommend you take a look at the manual there called New Car Features Manual for 2001. It doesn't have the details for working on stuff (those will be in the other shop manual volumes), but it's the one that tells you what all the new stuff is, why it's there, what it does and how it works.

For your next stop, you will want a good, Prius-capable code reader. The car is run by more than half a dozen computers and any time they flash warning lights on the dash, there is always information they can give you to help you learn what the problem is. Ordinary (non-Prius-capable) scan tools can read the basic emissions and engine codes, but not any of the other information you need for your car. Good scanners for a Prius are discussed in lots of threads on this forum (you can search), you don't have to spend very much on one, and you will use it a lot.

There are two batteries in the car: an ordinary (on the small side) 12 volt, and a much larger one for traction power. The traction battery is also what starts the engine. If the engine will not crank, one possible reason is insufficient charge in the traction battery. (But that's not the only possible reason; you need to read the codes from the computers.)

You don't need the traction battery working to be able to read codes. You can read codes as long as the 12 volt power is good. In fact, as long as the 12 volt power is good, you can use your scanner to read the condition of the traction battery.

Good luck with your project!

-Chap

 

Hi Tony - Roy from Canada - I bought 3 2001 prius just over a year ago and a fourth last week. I to was new to the prius but having an electrical background I have found the cars to be very reliable. All my cars had a problem with their high voltage batteries - I repaired all of the batteries myself and with help with the people on this site got all of them going.
The car does not have a conventional starter that is started by 12 volts - it uses the large 110 lb 273 volt battery to start the car - so getting this battery up and running is your first job. Here are some hints --

1) disconnect the battery 12 volt power and reconnecting it will clear service light and triangle - if you try to start the car 3 times and is does not start the cars computers will have to be reset by disconnecting and reconnecting the 12 volt battery.

2) Buy off the internet a cable and software (pirated from china) called techstream for 20 to 30 dollars, 3 weeks delivery probably.

3) Buy an old computer with windows XP installed and load the software and connect the cable to the computer,
4) This system will let you look at the cars computers and most important allow you to see the battery module voltages.
5) Read this site for further help

I will help you when I can as I am sure others will do. I do not look at this site everyday so I may be late getting to you for help - others will also respond as you ask for help.

Roy

 

I have a 2001 Prius that won't start. When I turn the key, it tries to start briefly and then shuts down. It seems like there is not enough power in the battery to keep it running. I guess that would be the 273 volt battery. Is there any way to charge the big battery? The problem began when the engine started misfiring presumably due to moisture in the plugs. I put new plugs and coil packs in it, but it got worse and just has that brief shallow starting noise for a couple of seconds when you turn the key. Does anyone have any thoughts or ideas? Thanks!

 

Check the throttle plate to see if it is sticking:
Cleaning Prius Throttle

Bob Wilson

 

Thanks, Bob, I will check it out this weekend!

 

Check it now, takes slightly longer than opening the hood and look down underneath the air filter.
TomK