S80 Water Sensor Faulty Connection

Sounds like a faulty water sensor circuit. Check the sensor's wiring harness and connector for corrosion or damage. A multimeter can help verify continuity and voltage at the sensor. What's the mileage?

Thanks! It's got about 222135 km on it. Do you know what voltage I should be seeing at the sensor?

At that mileage, sensor issues aren't uncommon. Unfortunately, without the Volvo-specific wiring diagram, I can't give you exact voltage figures. The sensor or wiring is likely the culprit. I would suggest visiting a workshop.

Thanks for the help. It was a bad connection at the water sensor, like I thought. Cost me 95€ to fix, parts and labor.