01 Prius HV battery ECU

Since your search has shown no availability of a salvage part, my opinion is that if a salvage part could be found, a fair price would be $500, which is ~50% of MSRP.

It is also interesting to contemplate why no salvage parts are available. I haven't heard that the traction battery ECU is a particularly failure-prone part.

If you should decide that you can't find a salvage unit, the price for a new part is $785 at Champion Toyota, Houston:
Champion ToyotaWorld

 

Car-Part.com--Used Auto Parts Market searrch junkyards around the usa

 

Good for you, can't beat that price. Hope that part solves your problem, good luck.

 

1. What DTC was logged by your car?

2. I understand the concept that a battery module might have an electrolyte leak to the metal battery case, resulting in a high voltage "leak" to ground, or a ground fault.

3. Since the battery case itself is just made of sheet steel, it's not clear what about it could fail.

 

I agree with Patrick, the "Battery Case" cannot fail, per se. Perhaps there is something inside the box causing HV current leakage. This can be inspected and tested for if you have the right tools and process. Toyota does not train their techs to repair batteries so they probably wont find it. The correct first question is indeed: Precisely which DTC's were logged?

Eric
Adopt A Part
800-508-2211

 

I've read a lot here about how corrosion forms on the connectors between battery modules on the Gen1. The ECU detects this as leakage to ground, and there is some level at which it decides that continued operation isn't safe. The solution is to either clean up the corrosion or replace the battery. If you go the replacement route, I'd recommend a unit with Gen2 modules in the Gen1 case. One company that does this is Remanufactured Hybrid Vehicle Battery Packs . I understand that Luscious Garage | Hybrid Specialists also does this for their local customers.

 

Patrick, for my education, what's a "HV battery ECU"? Is that the High Voltage battery that supposedly costs $10,000 at a Toyota dealership?

I'm trying to learn about problems the 2001 Prius has. My granddaughter has one that's giving her problems and she calls me for answers.....and of course I like to help her as much as I can. Right now her 2001 Prius won't start and she knows nothing about the car. I don't know much more. She hasn't had her Prius for more than a couple of months. Thanks Patrick.

I sent another reply to you on another thread early this morning as well.

 

The HV battery does NOT cost $10K. See Prius Battery Change is No Big Deal - Newsroom : Our Point of View Post / Toyota.

To help w/diagnosis, DTCs would be super helpful. Otherwise, we're practically flying blind.

You asked about a service manual in another thread. Unfortunately, they're not (legally) free and by themselves won't help you retrieve any DTCs. You can get access to them via https://techinfo.toyota.com/. People pirate this type of stuff too, but I'm not going there...

You might find http://www.autoshop101.com/autoshop15.html#Hybrid interesting/insightful.

What geographic area is the problem 01 Prius located in?

 

So glad to see that article cw. Thanks

Amen to that. What's the average cost to have this determined? Can codes be obtained from anyone other than Toyota dealers?

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I'm with you on this cw.

Interesting and insightful indeed. Thanks.

I'm in the lower northeast area of the USA.

Thanks for the input cw.....anything you can provide would be much appreciated. I'm just now beginning to learn about my granddaughters 2001 Prius. I'm assuming hers is considered 1st generation.

What are your first suspicions when a Prius won't start?

 

The HV battery ECU is an electronic control unit located within the traction battery case. The purpose of this ECU is to monitor the status of the traction battery.

There are 38 battery modules within the Classic Prius traction battery enclosure and the ECU monitors the voltage of each of the 19 module pairs. If the ECU sees that the voltage of a module pair differs substantially from the other 18 pairs, the ECU will assume that a module within that pair is bad. The ECU will log a fault which will cause the master warning red triangle to turn on, and a warning icon to appear on the MFD.

The ECU can also detect if a high voltage ground fault occurs (for example, if a battery module leaks electrolyte to the battery case) and if this happens it will log a fault and turn on the appropriate warning lights.

The traction battery is aka the "high voltage" battery. The replacement cost of that battery including labor will probably be ~$3-4K at your local Toyota dealer. Less costly alternatives are available if you can DIY the replacement or find an independent in your area willing to work on Prius.

 

They can be obtained by you (or your granddaughter) using an inexpensive ScanGaugeII that you can pick up at your local AutoZone type of place, or order straight from the PriusChat Shop to support PriusChat.

Just be sure to contact Linear-Logic (the manufacturer) and ask them to send you the altered cable that works in the 2001-2003 Prius, which they'll drop in the mail for free.

Then a number of us can help you through teaching the ScanGauge to read the interesting bits from the Prius, using the information in Classic Prius and ScanGauge. (It's a long thread and may look overwhelming in places, but at the end of the day it means a few people have worked out a whole lot of the secrets needed to read Prius computers and know how to make a ScanGauge do it.)

-Chap

 

I knew when I read the header of this thread that the the ECU was probably not bad. Toyota dealers are always replacing ECU's in vehicles, especially hybrids when they aren't really bad.

Being that your prius is an '01 model, I would just have to say on a hunch that it probably needs a new HV battery. Obviously, I'm as blind as everyone else here without any DTC's to look at. Another problem i have to wonder about, being how many of these corroded batteries I've seen is the sense-wires. They can often wick up the corrosion into the wire, sometimes all the way to the harness connector. Then they can become brittle and break in many places, which can cause all kinds of problems since the computer can't see the state of some cells.

 

Understood Patrick. Great explanation.

I'm assuming the warning icon (red triangle?) will appear in the dash screen. Is the screen call the MFD?

Also on the MFD?

I just called a local Toyota dealer and they gave me a price of $2,862 for the HV battery includes install and 6% tax (2300 + 400 + 6%). I was also quoted a price of $150 for the 12 volt OEM battery (includes 6%tax). This battery has the same size terminals as the original battery. I'm certain I can install the 12 volt battery. The service manager told me it was most likely the 12 volt battery (the reason it won't start). He also quoted $46 to run a diagnosis on it to get that code.

 

The master warning light, or red triangle, is a large warning light that will appear in the combination meter area. The combination meter contains the speedometer, odometer, fuel gauge, gearshift indicator, and various warning lights.

The MFD (multifunction display) is the touch sensitive screen located in the middle of the dash. If the car has a serious problem, then three warning icons will appear and one will have a different color than the others. That one is the one to be worried about. The icons can show a hybrid system problem, a traction battery problem, or an electric power steering system problem.

MSRP of the 12V battery is $139 and the dealer prices that you quoted are in line. No need to pay for diagnostic time yet; replace the 12V battery first and see if that takes care of the problem. Good luck.

 

1. Provides 12V power when the car is in any operating mode besides READY. This power is required to power up the various ECUs when the car is in IG-ON mode, prior to becoming READY. It is also used to power the various 12V accessories when the Prius is in ACC-ON or IG-ON mode. Once the Prius is READY, the DC/DC converter within the inverter will convert high voltage DC to a regulated ~13.8VDC to power the DC bus. Note that the traction battery is electrically disconnected from the inverter via system main relays located within the battery case, when the Prius is IG-OFF.

2. Provides an emergency source of 12V power if the DC/DC converter fails while the car is READY and underway. The steering and brake systems depend upon this power, as do the various ECUs, lighting system, etc. This allows the driver to safely pull over to the side of the road and shutdown the vehicle. A weak 12V battery will not provide power for long, and can create a safety hazard.