Mercedes X Klasse Diesel Solar Sensor Fault

A solar sensor fault can cause heating system problems. The sensor, also called a daylight or temperature sensor, sends data to the climate control system. Incorrect or missing data can stop the system from regulating heating properly. The error memory points to a possible issue. Have you checked the sensor's cable and plug connection? A bad connection is often the cause. Is the fault intermittent or always there?

I haven't checked the cable. Where is the solar sensor located in the X Klasse?

The solar sensor is usually on the dashboard, near the windshield base. Without diagnostic equipment and schematics for your model, finding the exact location and confirming a cable or connection issue is hard. Given the stored error and poor heating, plus a possible defective cable or plug, I'd suggest a workshop visit. A 95€ repair cost seems fair for diagnosing a simple connection problem, but it could be more if the sensor needs replacing.

Thanks for the information. The workshop visit revealed a faulty connection, like you thought. The 95€ estimate was correct.