Toyota iQ Water Sensor Fault

I also own an iQ, and these symptoms sound similar to what I experienced. If the water sensor is anything like the oil level sensor, it could be a bad connection. Have you checked the sensor itself for any visible damage?

I inspected the sensor and didn't see any obvious damage. How did you determine the connector was the problem?

Wiggling the connector made the symptoms appear and disappear, like a loose tooth. Given the diagnostic information, it's probably best to have the connections checked at a workshop. They have the proper tools to check the sensor's function.

Thank you for the advice. It was the connector; I had it replaced at a workshop for 95€. Everything is working as expected now.