Toyota Prius 2006 Lost Power! Help Please!

The reduced power and loud fan in the back almost certainly means you need a new Hybrid battery. Typically you would have the red triangle of death and other dash indicators to suggest a problem.

Check codes to make sure. Code reading options in my signature below.

As a california resident, you typically get 10yr/150k mi warranty on battery; however, there are conditions.

Good luck,

Steve

 

All this with no warning lights?

If no warning lights, then the battery is just very very hot. It then acts just like a bad hybrid battery which means you essentially have a squirrel for an engine. It will work, but not well.

Since you are in CA, and this is summer, this is possible. And since you bought it used, you don't know how the previous owner abused it. If you know the previous owner was a dog person, then you should really clean out the HV fan area.

 

+1 to the above.

You'd think I'd be more inclined to go there living in Phoenix and such...

The complete gutlessness of it steered me to failing battery as even when I'm at 1 bar with the fan on 6 in 110°F+, it's not as bad as he describes.

OP, if you're not using your A/C, USE IT. Keep you comfortable, and your battery should be comfortable. Run without A/C, and you're going to cook the battery.

 

get sunshades for the windows. you can find fan cleaning directions with pics on youtube.

 

Did you ever found the problem on your Prius? I been experiencing exactly the same issue you were having with an exact vehicle, almost same mileage. I have tried all the suggestions and still having the problem. Don't know what else to do.