Seat Altea Diesel Water Sensor Issue

The Altea's water sensor malfunction can indeed trigger the malfunction indicator lamp and cause rough running, especially in diesel engines. Given the error code points to an electrical fault, have you inspected the sensor's connector for corrosion or loose wiring? Also, verify the wiring harness leading to the sensor for any damage. A multimeter can be useful to check for continuity and voltage at the sensor plug.

Good shout on the multimeter. Where exactly should I be probing to check the voltage?

Confirming your suspicion, the error code associated with the water sensor malfunction often indicates an electrical issue within the sensor circuit. While probing the connector, check the wiring diagram for your specific Altea model. However, given the complexity of modern auto electronics, it might be prudent to consult a qualified workshop for a proper diagnosis and repair to avoid further complications.

Thanks for the input. Turns out it was the water sensor cable. Workshop sorted it for 95€.