Please confirm if this is real hybrid battery problem!

Yes this is a hybrid battery symptom, you will need another battery.

Usually when you postpone needed repairs, they tend to multiply and affect other systems. Your 2 battery failures are probably due to the age of the batteries.

 

Both these batteries failed with age. The hv battery probably was assisted by you not driving the car much, it got weak and out of balance and failed

 

An automobile 12v battery should NEVER be 10v. It's bad. It's old. It's bad, whatever, replace it. Fix the obvious first......then go from there.

Tech Tips & Tricks | How to Tell if Your Battery is Bad in 3 Easy Steps

Please read this link. It discusses 12v atv batteries but cars are similar. Have I mentioned a 12v car battery should never be 10v?

 

You have some classic signs of hybrid battery failure. For instance, the fan running will not be caused by a low 12V. That's due to thermistors in the battery bank sensing excessive heat.

 

Pending just means it is stored in memory. Many DTCs will not immediately trigger the lamp, on the first occurrence, but if it happens again on the very next start cycle, it will light the lamp. So..if you have one pending, it's waiting for the next start cycle to either clear itself, or trigger the lamp.

 

welcome!
you didn't really do anything wrong, old batteries fail, it's a fact of life, or science, or something.

 

Tires, brakes, light bulbs, batteries... They're all wear items that need periodic replacement.

There are options on replacing the HV battery. The dealer will want about $4500 for a new one installed. If you DIY, you could get several more months (years?) with individual module replacement at $50+. If you could find a wrecked 2009 with lower mileage than your current car, it would make sense to me to buy the battery out of it. It would not make sense to buy one from another 2005 as it would probably be in the same condition as your current one.

There are 28 battery modules in the full pack, and they don't all go out at once. Many times it's just a few modules that cause the problems. So the least expensive fix is to replace just the failing modules. But that can turn into whack-a-mole as other modules show their age. The dealer isn't even going to offer individual module replacement because you'd be very unhappy if the next module failed shortly after he fixed the first one.

There is a fairly new product on the market called a grid charger. It's a $400 device that charges the battery in a way that extends its life. Use the search facility for "prolong" to find discussions about it. Mechanics who do a lot of business with hybrids are going to have to get this sort of device now that the batteries are failing in significant numbers.

 

Welcome, Brian. Good answers above. I agree that the traction battery is almost for sure bad. And also, the 12V battery is absolutely a gonner at 10 volts.

I guess your decision is how much the 12 year old car is worth to you. I don't see any way it's worth the cost of a new battery from Toyota, but it might be worth a used or maybe even reconditioned battery. If you're handy, there are threads on replacing individual battery blocks. That would be the least expensive, but you won't get the best results without using the grid charger @RobH mentioned. Search for the treads on it. You can also read about it on Jeff's web site, Prolong Battery Systems. Extending the life of your hybrid. – Hybrid Automotive . In fact, if you're thinking of replacing battery components, you might think about getting the grid charger first and seeing what it does by itself. Some people have bought time just doing a full reconditioning with the Prolong. You'll want to get the discharger, too, to do it right.

To be honest, though, if you can afford to trade it in or sell it as is, at that age, I'd be wanting something newer anyway. My '05 was needing about $3,000 worth of repairs (not battery related) and that's what I did. So far, I like the results.