Prius exhaust temperature sensor issue

I had similar symptoms on my Prius. It sounds like you might have a leak in your exhaust system somewhere. That can throw off the sensor readings, like a bad thermometer giving you the wrong temperature because the window's open.

Interesting. So, could it be the sensor itself is fine, and the leak is causing it to read incorrectly? Where should I be looking for this leak?

Correct. If the exhaust system is compromised, replacing the heat sensor may only provide a temporary solution. The root cause may be a crack or hole in the exhaust component. Diagnosis by a professional is advisable to pinpoint the leak's source before any sensor replacement. The repair cost could be around 265€.

Thanks, that's a great analogy and helps a lot! I'll get it checked out at the workshop to diagnose the leak first. Turns out you were right, it was a small crack in the exhaust manifold, they welded it and replaced the sensor. Runs like new!