HV ECU replaced - Now needing new HV battery

It sounds like there's nothing wrong with the old hybrid vehicle ECU so having it reinstalled should not be a problem. The problem is the traction battery, which is going to be more than annoying when the car can't be driven. (If it can be driven now, the battery will quickly deteriorate to the point where the engine will be running whenever the accelerator pedal is depressed, and it will demonstrate very low power when accelerating from a standing start.)

So, the question is whether you would have agreed to pay $2,500 if you knew upfront that you needed a new traction battery - or whether you would have scrapped the car in its current condition.

Considering the car has 128K miles and the trade-in value is around $4K, its not obvious that putting that much money into a repair is a good idea considering the other systems that may fail in the next year or two.

 

If I were you, I will compare the cost of replace the battery (or maybe other component in the future) VS scrapping your current prius and find a new (or used) similar vehicle. Then I will go for the cheapest way.

That's what I did back then when my traction battery was dead.

 

Past posting suggest you have a handful of weeks, at best. Yes, you can get stranded.

Replace the traction battery from:

• Toyota new - least risk
• Rebuild using NHW11 salvage - same style battery but used ... pig in a poke
• Rebuild using NHW20 modules - middle price, very likely closer to Toyota new BUT we don't know about the earlier owner driving patterns.

Good, fast, cheap - pick two of three.

Bob Wilson

 

Regarding #1, I'd say you have at least a 30% chance that one or more of the following repairs will be needed in the next 100K miles:

1. steering gear, costing $2K
2. transaxle, costing $6K
3. inverter, costing $2K

The above prices are my estimate of Toyota dealer prices, installing new parts.

Regarding #2, I'd say there is a very high probability that you will be stranded given the cold winter season and the failing battery. As Bob indicated, this could happen within a few weeks or less.

 

Errr, I think we need to put "a 30% chance ... 100k miles" of an impending failure in context. Given an annual mileage of 15,000 miles, that would be:

• 15/100 ~= 15% of the expected life
• 30%*15% ~=
• 4.5% chance of failure in the next year

Recently I read a report on copper reclamation from salvage vehicles and found:

• 3% ~= approximate USA fleet salvage rate including accidents

So as one might expect, newer vehicles would have a lower salvage rate but as they age, the probability of a failure whose cost exceeds the resale value of the car increases ... if you are planning to sell the car. But there is another vehicle ownership strategy, "till the wheels fall off."

In September 2005, our 1991 Camry was in an accident that I drove away from and later, drove to the estimators. The estimated repair cost of just under $3,000 but the insurance company estimated the car worth just under $1,700. Since I had foolishly continued to pay collision, they declared the car a total loss, seized the title, and gave me a check for $1,200. It would have been cheaper for me to pay for the repair cost and continue to drive the car until something that was not body (aka., steering, engine, transmission) failed. The total cost of ownership:

• $13,000 - purchase price 1991 (not counting inflation)
• $1,300 - salvage price 2005
• $20/yr. - oil changes
• $450/5 yr. - tires (was due)
• $10/yr. - lights, air filters
• $400/10 yr. - timing chain (was due)
• $500/yr. - insurance (estimated)
• ~185,000 miles - odometer at crash
• 32 MPG - vehicle lifetime average (my records)

11,700 = 13,000-1,300 capital cost
300 = 20*15 oil changes
900 = 450*2 tires
150 = 10*15 lights, air filters
400 = 400*1, chain replacement
7,500 = 500*15, insurance
8,670 = (185,000/32)*$1.50
------
$29,620 ~= total cost of ownership

~$0.16/mile
​

But this is total cost per mile. There is something simpler called the 'capital cost per mile' and major repairs can be considered a capital cost because it replaces buying an equivalent value, high-mileage, car. This is part of "driving until the wheels fall off:"

$0.064 / mile - pre-accident (capital/miles)
12,333 mile/year - pre-accident miles per year
49,333 miles - estimated 2005-2009 miles
$0.061 / mile - post-accident with $3k repair
​

Nothing in life is guaranteed and the longest running USA Prius had 350,000 miles before being totaled in an accident. So it comes down to placing a bet against what will take any vehicle out of service. In my case, it was foolishness to continue collision insurance when the car value decreased to what I could cover in collision repair. But then I wouldn't have bought a used 2003, Prius with 49,000 miles. <grins>

My 2003 Prius has over 120,000 miles, fully paid off, and no more collision insurance. If something fails, I'll fix it myself ... within reason. I don't do body work.

PART FAILURE TABLE NHW11s

	Column 1	Column 2	Column 3	Column 4	Column 5	Column 6	Column 7
0	part	Est$	impact
1	throttle plate sticky	$10-20	car fails to start	retry works sometimes	2-8 weeks
2	accelerator encoder	$100-500	car limps home until replaced or refurbished
3	throttle plate encoder	$700	car won't start	engine erratic	stops moving 1-2 days
4	steering encoder	$1	000-1	500	steering shudders but car is somewhat driveable
5	HC catalytic converter	$100-1	500	corroded linkage	bad O{2} sensor	bad HC converter
6	transaxle failure	$1	000-4	000	car first hums/rumbles	throws codes	stops moving 2-8 weeks
7	traction battery failure	$500-3	000	car throws codes	poor performance	stops moving 2-8 weeks

.
Based upon the reports and what I've seen in failed part analysis, this is my opinion:

• throttle plate - clean the throttle plate area when you change the oil in the fall or at least once per year
• accelerator encoder - I'm seeing about two failures per year and mostly the 2001 models.
• throttle plate encoder - only one know instance in four years
• steering encoder - seems a steady rate of about one per year and biased towards the 2001 models
• HC catalytic converter - most common failure, 2/3d is corroded linkage, some O{2} sensor failures, and at least one replacement, ~1-2 per year.
• transaxle failures - about 1-2 per year but very hard to quantify. I suspect a latent manufacturing defect that was corrected and may be related to the potting compound or processes used with the stator windings.
• traction battery failure - appears to be a systemic weakness in the NHW11 modules, weak terminal seals. A Toyota TIS tried to address the 'short to ground' but using a sticky, external sealant but IMHO, not terribly successful. The NHW20 modules are much better constructed and should be considered for future traction battery refurbishment.

Bob Wilson

 

I sold the 01 I fixed with 123k miles for $6300 last week. With battery problem more likely no body is going to buy it.

I say the heck with a dealer fix it yourself some of the tech. are part swapper and dumb as a mule I took matter in my own hand and solved my problem - very tough one actually.

 

Yep you go the dealer they will suck you dry It is unbelievable to swap the HV ECU for that much money and not do a test before giving back to a customer. The HV ECU is piece of cake and you can do it yourself for less than $100 buying used one on Ebay if that is what is wrong and need to fix the car. You have to watch for the immobilizer resetting other than that just plug and play. If you wonder how i know all this go read Problem Car topic on Gen1 posting you will find a longggg discussion there. I had one of the toughest, longest, messiest, most costly repair that i ever encountered and i did the work myself too and bought used good parts. I replaced just about everything there is for the hybrid portion: battery pack, inverter, hv ecm, transaxle. The car did fixed and i sold it last week 01 PRius 123k miles for $6300. Buyer loves it drove perfectly in all aspects.

Now it looks like you have a battery pack problem. I say go replace the subpack only and the heck with replacing the whole pack that costs thousand of dollars unnecessarily. I am 100% certain you have few bad subpacks in there not the whole 38 of them. I have many good subpacks from the job i did for the 01 at the time i did not know about replacing the subpack. I will sell it to you at a reasonable price and it comes with instruction from me to do it. I bought the whole pack last year for $1k to fix the 01 when i did not know about subpack replacement only. While you are at it you might want to clean up the corrode terminals which is one of the problem on first gen. Prius.

One of the instrumental tool to help fix PRius is a good scanner. Mine is software base with OBD2 adapter than can scan generic and Prius. I paid extra for the Prius and CAN bus upgrade. I fix gas, diesel and hybrid so i need this good scanner when i was a used car dealer. I am one of the few rare mechanic and car dealer that also into green, eco stuff. I am driving a veggie Mercedes Benz on the used processed cooking oil i make myself.
Trust me you still can fix the Prius without it but you are shooting dart with your eyes being blindfold.

Good luck with the repair and if you are in FL somewhere i might buy your car as is as i am in the process of moving to near Orlando by the end of this year 2009. I am out of Ca indefinitely

 

I would strongly consider rebuilding the battery using gen II modules. I myself have done it in 4 cars. I did one 2 years ago and its still on the road lookin great after 40k miles. Check out my website with detailed instructions on how to rebuild your own battery yourself at home for less than $500 if your doin the whole battery or less that 50 if you just need to replace 1 module.

hybridbatteryrebuild dot com