2005 Prius P0a80

Odometer reading? If under 100K miles your battery would still be under warranty.

Yes, DTC P0A80 means that the traction battery has failed. I'd expect you to notice some driveability issues, like the engine running whenever you depress the accelerator pedal, and reduced mpg.

If you don't notice any issues, then I suppose you could continue to drive the car and see what happens. Or you could take your car to the Toyota dealer and see what DTC the dealer tech can retrieve.

 

my mother is the owner of a 2005 prius 109k, I try to borrow it as much as possible because of its great gas mileage, yesterday I get in the car, drive it for about 20 minutes, I notice the traction battery is charging and discharging quickly and then I get the same thing triangle, circle with !,vcs, check engine. I also hear the battery fan for the first time turn on (it was about 30 degrees fahrenheit. I got the ODBII and indeed got codes P0A80 and P3012, I want to fix this before my mother finds out, I'm willing to buy a re-manufactured battery. I like this car so much I couldn't sleep last night thinking of how to fix this, I want to return it to my mother without her noticing anything went wrong with it, she's on vacation and will be back in 3 weeks. Thank God for this forum. Please need some urgent advice..

 

the big expensive battery helps drive the car, and helps your mpg, as it gets older I find mpg increases (a few years break in period) but I'm sure as it gets really old mpg starts to go down as it begins to die.

my question is why couldn't toyota design the car to run properly with a dead battery? So that the only consequence of a dead battery would be poor mpg, not a dash full of warning lights.

 

The car needs the battery to operate the transaxle, since the planetary is connected to an electric motor.

Elmo, contact Ron et. al. at http://www.hybrid-battery.com. I have the utmost respect for them.

 

We have seen a few 2005 Hybrid battery failures lately.
I bet most are corrosion of the bus bars and interconnect.
Only way to tell is take the cover off and take a look.

 

It sounds like your mother's car needs a replacement traction battery. You can buy a "remanufactured" one, or you can buy a salvage battery from a newer crash vehicle.

If you want traction battery fault-tolerance, buy a Honda hybrid. Of course, the disadvantage of that choice is that the Honda hybrid system is much less elegant and less fuel-efficient. There are many recent stories of Honda Civic hybrid owners complaining about much-less-than-advertised mpg, for example see:

http://www.latimes.com/business/la-fi-autos-honda-hearing-20120126,0,262230.story

The Toyota hybrid system is fully-integrated, which results in the best-possible efficiency. The bad news is that the system is not fault-tolerant, so if something fails you must fix it. You cannot limp along for an extended period.

 

I almost did buy a CR-Z 6 speed but it didn't have rear seats, I joined a CR-Z forum and found out that a lot of owners are ripping their batteries out since it helps so little (honda is mild vs toyota full hybrid) so you are obviously correct that Honda's Integrated Motor Assist doesn't have a problem running with a dead or missing hybrid battery pack. Honda came so close to making the CR-Z a perfect 2 door car, but alas they came up short.

 

yes, p0a80 is a bad traction battery, it will run fine for a while, then later out of nowhere it wont go past 20mph, not cool specially in rush hour traffic in NYC , I got the battery replaced by reinvolt, had the car shipped to NC from NY, they refurbished the battery and reinstalled, then I took the bus down there to pickup the car, total with shipping of the car, battery replacement and bus ride to NC, $2,580. I did notice on the way back that the battery level fluctuates allot less, I saw it go down to one bar below green in nyc after allot of ev stop n go in traffic, so far so good averaging 45mpg, hopefully I'm good for another 100k+ miles.

 

You would lose that bet. Bus bar corrosion was a significant problem in Gen1 batteries but the improve Gen2 batteries dont leak often. The Gen3 modules are even better than the Gen2 - lower series resistance which means higher current rating (130 vs 100 amps)) and less average heat generated.

The Gen2 failures that we are now seeing as the 2004/2005 Prii age come in two main flavors:

1. One module with a bad cell (That's what happened to my 2004 at 195k miles). This appears to be the majority failure mode. It happens as the 28 modules become unbalanced and then when the HV battery is deeply discharged (20-40%SOC) one cell in one module gets reversed and can never recover. The P0A80 code is then triggered as the HV battery is recharged and the battery ECU detects a 1.2v module pair voltage difference.
2. Multiple module failures due to the HV battery getting overheated. Two possible causes:
   1. Clogged cooling fan - discussed heavily in several threads. Usually due to pet hair or in Taxis (large number of short trips with back seat passengers)
   2. Prii in hot climates - exacerbated by not using the AC.

JeffD

 

Thanks Elmo. It helps others here when posters update us as to their issue was eventually resolved.

 

Where in NC did you get this done? I need to replace mine and am looking for a place to do it. Thanks.

 

That would be Taylor Automotive in Sanford NC (The originator of ReInVolt).

JeffD

 

thanks!
on pc i found mac's service center in Ashland VA with good reviews. Talking to them now.