S80 Heating Output Too Low

I had similar symptoms in my S80. The temperature sensor might be the culprit. Did you try checking the sensor calibration?

Thanks for the suggestion. Where exactly is the temperature sensor located, and is any special procedure necessary for checking its calibration?

I did not check the sensor calibration myself. I took it to a workshop. They confirmed the sensor fault and replaced a defective cable. I recommend you do the same.

Thank you for the advice. I followed your suggestion and visited a workshop. The cable was indeed defective; the final repair cost was 95€. The heating now works as expected.