Prius engine power loss

Sounds frustrating! That happened to me a while back. Have you looked into the main relay that feeds the engine control unit? When that relay starts to fail, it can cause all sorts of weird issues, like reduced power and ECU errors. It might be worth checking before you start thinking about replacing the whole computer or something. Is the car struggling to start as well sometimes?

Thanks for the suggestion! Where is the main relay located, and how would I check if it's defective? I'm not really sure where to start looking for it. And no, the car starts fine, maybe a little bit slower than usual but nothing alarming.

Okay, so if it starts fine, that could indicate it's not a completely dead relay, but it's still worth checking. Honestly, unless you're comfortable with automotive electronics, finding and testing the relay can be a pain. I ended up just taking mine to a workshop, and they diagnosed it quickly. The mechanic confirmed it was the main relay and replaced it. It's probably the easiest way to make sure everything is done correctly! A new ECU can be really expensive.

Thanks for the advice! I took it to my local mechanic, and you were right! After diagnosis they told me that the main relay was defective, and it was causing the ECU to throw errors. They replaced the faulty relay; the final repair bill was around 120€. Now the car runs smoothly without any errors. Thanks again for pointing me in the right direction!