Water temperature sensor error code

[Luigi Morales]

So I’m getting a water temp sensor error code on the smart craft. Boat still runs but idle speed only. A couple of times I got it up to 29 mph. But then it shut down.
Idle speed only the rest of the time.
Will just the sensor cause this problem or is my impeller failing. Temp reading 176-189 degrees while engine was on.
Mercruiser 496 2007 sea ray 270 slx