Does this mechanic's assessment ring true to anyone?

1st: there are two batteries. There's the ordinary 12v battery that runs the dome light, starts up the dashboard and computers.

Then there is the hybrid battery, which is the big one.

The large hybrid battery is what starts the gas engine, but it should be understood that the engine won't start unless both batteries are good.

The small 12v battery to boot the computers, then the large 144v hybrid traction battery that actually starts the engine just to write it a different way.

This "corrosion of the brake booster" doesn't make much sense here. There is a brake booster, it can have problems, but it isn't anywhere near either of your batteries, so it's hard to figure out what your mechanic might have meant.

It is reasonable to believe that both of your batteries are dead or dying. The hybrid battery is meant to last 8-12 years, and that typically skews on the low side in cars that see infrequent use. The 12v battery tends to be good for about 6 years, so you ought to be ready for your 3rd by now.

A recap: I would expect a multi-thousand dollar quote for battery replacement, it plausibly is about the right time for that, and doing so would make that into a real cherry of a car. But I don't understand what (might be) going on with the brakes.

 

toyota aqua? is this a chatbot?

 

Adding: there is a considerable difference in quality (and sometimes warranty) when you get the hybrid traction battery from Toyota. They're the only source for proper new ones.

Rebuilts are a bit sketchy, and lately they don't save much money vs. the real deal from Toyota.

 

the master cylinder and the accumulator control the brakes

 

Prices r too low to turn a profit he's nuts

 

All used parts with probably 10x the mileage of the original OP car on them. I'd take it to another shop, something doesn't "smell" right.
I definitely wouldn't put a used traction battery into it at that price, when a brand new dealership traction pack is @ $1700. I've seen that price mentioned recently.

Just my humble opinion......

FWIW, you've got a parasitic electrical draw somewhere that needs to be tracked down and repaired - not just throw parts at the car and hope the problem goes away. Since it's not a daily driver, I'd look into trading it in for a simple gas car. Your not saving enough gas money to justify the car, and resale value on a car like that is very high for now.

 

Isn't the Aqua identical to the Prius C? Just the Aqua was a Japanese market name?

A 37k mile hybrid battery of that year is a diamond in the rough and would easily be repairable to provide many more years of service.

If the car is not starting due to a P0AA6 (leakage) issue, that could easily just be one module needing replacement, or just a good cleaning to remove any electrolyte seepage.

 

Toyota Aqua? Must be a BOT...only has 4 posts.
But if anyone has a hybrid they don't drive much, it's best to sell it....hybrids are NOT like ICE in that rarely being used is okay...it is not, those batteries need to be used and charged or they die an early death. If they need a vehicle for minimum use, best to get an ICE or and EV they can leave plugged in all the time....can't plug in a hybrid unless it's a Prime and, in that case, why spend all that extra money for non-use?? Makes no sense.

 

Yeah this seems fishy all around. I wouldn't want a used hybrid battery in the first place, and certainly not when it was so close to the price of a brand new one with full warranty.

And used master cylinders and accumulators are really tricky in the first place. There are many different versions that do not interchange with each other, which makes it hard to source exactly the right one in used-but-not-used-up condition.

I'd look for another shop.