V70 Reduced Engine Power

I had a similar issue with my V70, although it was a while back. Reduced power and increased fuel consumption definitely sound familiar. Has the car been making any unusual noises, especially from underneath? It is possible the temperature sensor is faulty, or the sensor is correctly reporting a problem elsewhere, for instance further down the exhaust system.

No, no unusual noises. I mostly drive on the highway. You mentioned further down the exhaust system, what exactly could be the problem there?

In my case, there was a small leak in the exhaust system before the catalytic converter. The leak was causing the exhaust gases to cool down too quickly, which the temperature sensor then detected. The ECU (Engine Control Unit) then reacted by reducing engine power and increasing fuel consumption to compensate. If the exhaust system is faulty, you will need to get it repaired in a workshop.

Thanks, that's really helpful. I'll take it to a trusted workshop and ask them to check for leaks in the exhaust system. I hope that fixes the problem. It would explain the error message from the temperature sensor, too. They did indeed find a small hole and had to exchange parts of the exhaust system. It cost me 265€, but the car runs fine now!