hv battery dying?

Hello smart people. I have been reading PriusChat threads for months now, but I just now made an account. I know very little about cars (except what I've read here), so I appreciate your patience and understanding.

The other day, I was operating my 2007 Prius normally when the following warning lights turned on:

• The triangle of death
• Brake system warning light ((!))
• VSC: Vehicle stability control
• (!): tire pressure (but this has been on bc I know my front right TPS is shot)
• I can't remember if the ABS light came on, but it may have.

When I was parking the car at the mechanic, my power steering failed as well. Luckily the lights came on close to home. I forgot to take a picture, like a dummy.

Anyways, they ran the computers on it and diagnosed a dying hybrid battery. I did not get a chance to see the trouble codes. After doing some further research here on PriusChat, I am reluctant to dish out the money for a replacement until I know FOR SURE that this is the problem.

Here is why it may in fact be the hybrid battery (besides the obvious computer diagnostic):
(1) The mechanic noticed that my Prius wasn't following the usual cycle with the electric/gas motor upon starting the engine.
(2) I have experienced weird fluctuations in battery power/capacity within the last week.
(3) My car has 147,000 miles on it with some change, and I drive it ~80 miles a day. I assume that the current hybrid battery is the original (I bought it from a private seller and have no access to that info). They do tend to fail around this time.

Here's why I am second-guessing myself:
(1) I took my car to the Toyota dealership for a diagnostic A MONTH AGO, and they detected no milage drop and no battery issues.
(2) The dealership DID notice that my water pump was seeping, and it looks like these warning lights could be triggered by a failed water pump.
(3) Perhaps the failures are linked to a 12V battery failure? The only potential symptom of that is that my AUX cord plugin hasn't worked for some time now.

What I plan on doing is (1) self-testing the 12V battery when I get home from work today and (2) asking the mechanics to run the computers on my car again so I can see the trouble codes. Thing is, will the trouble codes even show up this time if he cleared them?

Based on the info I shared, do you think it is, in fact, a hybrid battery failure?

 

this lovely cocktail of warning lights came on in my 2007 prius this weekend. in case you can’t see the image, we got:

(1) triangle of death
(2) vcs light
(3) brake light ((!))
(4) check engine
(5) the car with the ! on the monitor

the car has 147.6k miles and ran well until this weekend, lmao. i bought it used at 132k; no history. i assume this is the OG hv battery. i drive ~90 miles a day to commute to and from work.

my 12v battery isn’t the strongest, but i did the vehicle signal check self-test and it looks like it’s still going. (12.1v before unloading, 11.8v after unloading, 14.4v upon starting)

have also been experiencing abnormal hv battery fluctuations since the warning lights came on. before that i hardly noticed it.

i assume this is a hybrid battery issue? it seems about time for it to go out all things considered. but i want to consult the experts (the priuschat minds) before spending a paycheck or two on a new battery.

thank you!!

 

ah, you guys are the best. thank you for your helpful replies!

so the more tests i do the more it seems obvious that it’s the traction battery. per andy’s suggestion and suggestions from other threads, i got a reliable bluetooth OBD scanner and the Dr. Prius app. you can see the results of the tests i ran tonight - the first is a photo of my battery status while running off the battery only, while the second photo was when i was braking.

as for the battery life test, dr. prius seems to think my hv battery is toast. i did buy the car used at 132k miles, so this is to be expected. the more i read about what a healthy prius should be like, the more i realize that maybe what i thought was “normal” was actually a dying battery. i wish i had read these threads sooner!

my plan is to have the error codes read one more time this weekend at an auto shop, and then have the battery completely replaced on tuesday.

i’ve hired a mobile hybrid battery replacement service hybrid2go - they have abnormally good reviews, but they seem legit. i gave them a call just to be sure and felt good about it. their batteries are refurbished but come with a lifetime warranty, which is great in case it fails again down the line.

based on this info and the attached data, do y’all think that completely replacing the hv battery is the way to go? if so, what is your opinion on hybrid battery services that AREN’T the dealership?

i’m not really in a place where shelling out 3 grand is an option, but I’m open to other recommendations if you have them.

thank you!

 

replying again - i am no expert at reading the battery bars there in my attached photos (i’ll attach them again here for reference) but it seems like only one of my cells is out. is that correct? should i replace just the one cell or the whole dang thing?

 

hi y'all, i figured i'd update here -

it was, in fact, blocks 11 and 12 that were weak. thankfully, the battery replacement went very smoothly. the car runs much more efficiently now and i saved a lot of money by hiring hybrid2go instead of going to the dealership. my average mpg is way up, yay!

perhaps this is a question for another thread, but maybe you guys would know - since I've replaced the hybrid battery, i expected my car to depend on the electric motor more. however, the gas engine turns on after like, 2 seconds of acceleration (at reasonable speeds, too, like 0-35).

Even driving on the freeway at 65 miles per hour (a reasonable speed for a car like the Prius), my car tends to run on only the gas engine, and never the electric motor for more than a few seconds. it only makes heavy use of the electric motor when i stop and when i go up hills.

I'm wondering if it's because the computer is used to running with a weak battery. However, the guy who installed my new traction battery had to unplug the 12v battery for 30 minutes or so, so that would have reset it, right? I'm not sure why it uses the traction battery so lightly still. would any of you have any advice?