2006 prius high rpm and no acceleration (randomly)

1) Hybrid battery warning light is ON P0a80, Module 8 is under performing. ( expected)

 

One or more of your 28 battery modules in your hybrid battery pack need to be replaced. Probably have some corrosion issues on the plates between the batteries too.

It's a pretty easy fix once you absorb all the information of how everything works and get past the intimidating nature of being safe with a high voltage system that your certain is properly disabled. There's plenty of people that do this as a mobile service that are on Craigslist. Many of them are more interested in getting your valuable low mileage battery modules, than just replacing the one bad module though...

Reason Craig's list folks are finding work doing this is because Toyota dealership and most auto shops fix cars not batteries and electronics so they always say they aren't serviceable and you have to replace the whole battery pack for $2,500 to $5,000, but that's not the case with Prius.

If you're lucky, the problem could be a clogged hybrid battery cooling fan or a bad 12volt battery, so I'd start there first. Use google to search on Priuschat for tons of info about how to do all of this.

 

That code is for the entire battery pack not just the specific bad module in the pack. It'd be awesome if they had a code for each of the 28 modules, or even just which of the 14 books that make up the 28 modules, but Toyota is in the business of selling new cars, not getting you to drive your old one around for 20+ years, so they prefer people get another car soon as P0A80 shows up.

 

I assume there was another code that specified module 8? If so, there's your problem right there.

Cheap way out is to just replace that module. But then you'll be replacing another and another and another. It would probably be a big help if you used a Prolong grid charger to balance the cells after replacing the bad one, but the others will still be old. If you plan to keep driving this car and don't want to be fixing it every few months, either get a whole new battery or else a whole used (not rebuilt) but near new battery.

 

Since the car has low mileage, you should just buy a new battery. Then it'll be good for 10 years

 

The battery is dead or dying, and when it goes low enough the vehicle will try to recover by ramping up the RPMs.

How long were you wanting to drive it before replacing/fixing the known bad battery?

 

You won't know if there's an additional problem until the back breaking work is done. You already know the battery is bad so tackle that first. Chances are there's nothing wrong with the engine as it's still low mileage. The things you're noticing is probably from the failing battery.

 

+1 to both @SFO and @JC91006. If the battery can't help meet the power demands, the engine will do its best to try to compensate. Up to a limit, higher rpm = higher horsepower.

 

This sounds like my original problem.
No Codes
High RPM might be what I had. Running a scan gauge I noticed battery slowly discharging to 2 bars and below on freeway driving, but when attempting to climb a hill would lose power after the engine ran at high RPMs but did not get the additional boost that the VVT is suppose to give by advancing the timing. The VVT only works at low take off and high speed for extra boost. Result the battery was low and did not supplement the engine for required extra power on hills to keep the speed. Replaced the VVT valve and it solved the high RPM, Returned power, and on freeway straight and level added engine RPM to slowly regain the 60 % SOC required.
Would suggest you check the VVT valve and its filter. It solved that High RPM no power problem and I regained power for hills and highway recharging back to SOC that Toyota is 60%, the optimum they are shooting for.

The high heat adds problems and just did a trip to Phoenix followed to Eugene Springfield OR from Reno. The heat keeps the new drive battery still hot and its fan changes speed seldom to help cool.

My new problem is I get a RED master warning, Yellow Brake, and a YELLOW VSC warning lights every 600 or so miles when on long steady driving. No codes are pending or saved. A restart clears these warning lights and it runs normally. I think its high temperatures and long high speed driving 65 to 70 mountan driving.

So I solved the High RPM and no power problem, and now have a warning light problem with no codes that reset like a computer with a reboot (restart engine) just as mentoned in your post. I don't know if this might help as the heat is a new problem.

 

Your seeing high rpm because there is not any hybrid battery power participation. Its basically asleep back there which leaves the tiny little 90 horsepower motor to provide all the power. You cant under stand why the car has no power so you floor the pedal to get it going. Your creating the high rpm.

Your car is sick and your flogging the engine to provide the power you want instead of taking it easy on the car cause the battery is dead.

Without the powerful hybrid battery contribution its an anemic little car.